CN110441677B

CN110441677B - Automatic relay tester who disposes

Info

Publication number: CN110441677B
Application number: CN201910724762.9A
Authority: CN
Inventors: 凯文·马克·柯蒂斯
Original assignee: Kai WenMakeKedisi
Current assignee: Kai WenMakeKedisi
Priority date: 2018-09-04
Filing date: 2019-08-07
Publication date: 2021-06-29
Anticipated expiration: 2039-08-07
Also published as: TW202011040A; CN110441677A; TWI704363B

Abstract

A tester for a relay includes a housing, a test circuit including a controller, an electronic switch assembly, a power source, an indicator LED, a test enable switch, a relay type switch, and five electrical leads each connected to one terminal of the relay. Setting the relay type switch to the relay type under test, powering each lead, and activating the test enable switch, the controller may ground each lead in turn and then count the number of other leads that are thus grounded. The controller then illuminates at least one indicator to indicate a passing or failing relay test based on the measured count. Once the leads connected to the relay coil are identified, a cycle test of the relay may be performed.

Description

Automatic relay tester who disposes

Cross Reference to Related Applications

This application claims priority to us provisional patent application 62/765633 filed on 2018, 4, 9, which is incorporated herein by reference.

Statement regarding federally sponsored research and development

Not applicable.

Technical Field

The present invention relates to testing equipment for electronic components, and more particularly to an automatically configurable relay tester.

Background

Relays are mechanical devices used in many types of equipment, automobiles, and the like, which allow a small power signal to control a relatively large power load. For example, in an automotive circuit, a relay is generally used to control a headlight circuit. A light switch operated by the driver of the vehicle is connected to the input or coil side of the relay. This input side requires a relatively small amount of power from the lamp switching circuit. When the headlight switch is switched to the on position, power is applied to the coil, causing a magnetic field to be generated about the longitudinal axis of the coil that in turn attracts a ferrous metal pole piece on the output side of the relay, causing a contact change state that causes the headlight circuit to close, thereby powering the relatively high power headlight circuit. In effect, the relatively small power drawn from the headlamp switch circuit controls the larger power delivered to the headlamp circuit. This type of configuration is used in all different types of electrical/electronic control of entire industries and equipment, automobiles, tools, automation equipment, and almost any equipment that requires some type of medium power control.

Each electrical or electronic circuit containing a relay creates a test problem to determine the cause of the fault, particularly when the faulty circuit is of the automobile type, so that the test points that can be checked are inaccessible when the circuit is in a running or "live" state. All relay circuits consist of control (coil) and load side. All relays include a coil powered by a control circuit which in turn causes the relay to operate at least one mechanical contact to cause a connected load circuit to be energized or de-energized by operation of the mechanical contact. When a problem occurs with this type of circuit, it is necessary to check the voltage and current at different locations within the circuit to determine the cause of the problem. If there happens to be an easily accessible test point in the circuit, a voltmeter and ammeter (digital multimeter-DMM) can be used to display the power level of the circuit. A disadvantage of using DMMs is that it is time consuming and particularly difficult to obtain a current reading in the powered circuit. The DMM also cannot automatically measure the relay to determine if the relay itself is faulty and the cause of the circuit fault.

There are relay testers in the market today that perform automatic relay testing. My "Relay Buddy^TM", U.S. patent No. 9423462 is the best example. The present invention is an improvement over this type of device because an interface is created between the Relay Under Test (RUT) and the relay tester itself.

Relay testers on the market today all contain some universal relay sockets so the RUT can simply be placed into the appropriate socket, thereby exposing the electrical components of the RUT to the appropriate location in the relay tester where the circuit is tested. For these types of relay testers, it is required that the RUT be able to fit into the particular relay socket to be tested. Relay Buddy^TMThe 3 specific types of relay sockets or testable terminal layouts "footprint" are standardized. Relay Buddy^TMOther relay footprint adapters are also provided to test several other types of relays by aligning the RUT terminals with the correct test socket terminals. All objects of the prior art devices comprise a fixture or fixtures to allow RUT to be controlled, known and repeatableIs connected to a relay tester.

This is a real limitation of such current mode relay testers. Relays that can be tested are simply able to fit the appropriate footprint provided by the tester, or they must have adapters that allow the relays to fit the correct terminal locations.

All relays contain a coil that is energized to create a magnetic field that in turn pulls the armature or pole piece of the relay switch to move, causing the electrical connection to close or open. When the power supply for energizing the relay is removed, the magnetic field will be lost and the armature will return to its original position under some type of spring force, and again produce the original "power off" or "normal" electrical connection condition. Thus, all relays contain a coil side and a switch side. Most modern automotive-type relays contain a common "footprint" that allows the components of the relay to be properly and repeatably positioned whenever placed in an electrical circuit. Automobiles and most other devices that use relays contain "sockets," which allow the relays to have a common and properly configured connection point into the circuit.

Further, all relays contain coils and switches, but there are many different types of "footprints" or configurations of those common components that expose the relay. Depending on the amount of current the relay is designed to handle, it may include a relatively large terminal exposing the circuit switch side. Some relays designed to carry over 100 amps typically have switch connections using large round screw terminals.

Modern relays do not have strict wiring standards, resulting in the terminal names/sizes being a common known location or function. In order to successfully test the relay, an adapter must be present to properly connect the appropriate relay terminals to the tester so that the tester knows which terminal is which.

Therefore, there is a need for a relay testing device that can be quickly connected to a relay without having to know what each terminal of the relay is. The desired invention will have easy to use and intuitive controls and can quickly test 4-terminal or 5-terminal relays giving a clear indication when such relays successfully pass or fail the test. The present invention is relatively easy to use with a vehicle battery or an on-board battery. The present invention achieves these objectives.

Disclosure of Invention

The device is a tester for a relay of the type having four or five electrical terminals, two of which are coil terminals connected at opposite sides of a relay coil, or a single normally open terminal or a single normally closed terminal, or a normally open terminal and a normally closed terminal, and an armature terminal electrically connected to a conductive relay armature, if present, which is connected to the normally closed terminal when the coil is in a de-energized state, or to the normally open terminal when the coil is in an energized state. Such a relay is either a normally open terminal relay, a normally closed terminal relay, or a terminal relay having a normally open terminal and a normally closed terminal, and is generally used for a vehicle (not shown).

The tester includes a housing and a circuit board at least partially secured within the housing. The circuit board includes a test circuit including a controller, two or more electronic switch assemblies, a power source, at least one indicator, a test enable switch, a relay-type switch, at least five voltage dividers, at least five analog-to-digital converters, and five electrical leads, each electrical lead terminating at a conductive clip at a distal end thereof.

In one embodiment, the power source is a battery or the like contained in the housing. Alternatively, the power source is an external power source, such as a vehicle battery having a positive power lead and a negative power lead, each connected to the test circuit to power the test circuit and the relay coil.

In some embodiments, at least the indicator includes a green LED to indicate that the relay test passed and a red LED to indicate that the relay test failed. In some embodiments, the at least one indicator comprises-a terminal LED to indicate that the relay-type switch is set to the first position, and-a terminal LED to indicate that the relay-type switch is set to the second position.

Due to the "pull-in time lag" of the relay, the controller is adapted to enable a fast count of the number of electrical leads that are grounded by grounding one lead before the relay changes state. Wherein the armature does not move immediately when the relay coil state changes. The controller is also adapted to effect an alternating slow count of the number of electrical leads that connect one lead to ground, waiting until after the armature movement time once the relay has changed state.

Preferably, the test circuit further comprises a voltage regulator for providing a component voltage, for example volts, to the test circuit when the supply voltage is higher than the component voltage. A diode bridge may also be used to correct the polarity of the component voltage if the power supply lead is inadvertently connected to the wrong side of the external power supply. In some embodiments, the resistors may be varied to accommodate external power sources having voltages of 12 volts, 24 volts, or the like.

Preferably, once the controller determines which electrical lead is connected to the relay coil, the controller is adapted to run a predetermined number, for example ten cycle relay tests. Thus, the controller illuminates the green LED if each cycling relay test passes, or the controller illuminates the red LED if any cycling relay test fails.

In use, each electrical terminal of the relay is connected to one lead of the test circuit and the relay type switch is set to the type of relay being tested and, with the test enable switch activated, the controller may set each electrical ground, and vice versa, and then count the number of other leads that result in grounding. The controller then illuminates at least one indicator to indicate a passing relay test or a failing relay test based on the measured count.

For a 5-terminal type relay, and in the event the relay is de-energized, the test circuit first determines which of the five leads are connected with substantially zero resistance and then designates them as normally closed leads. The test circuits are then in turn grounded to each other to see when the normally closed leads are open, with essentially infinite resistance. This indicates that at least one coil lead is found. Once one coil lead is determined, the coil can be cycled in a cyclic relay test to identify the other leads and the relay is typically tested over ten cycles. If any test fails, the red LED lights up to indicate that the relay test failed; otherwise the green LED lights up to indicate that the test passed.

The present invention is a relay testing device that can be quickly connected to a relay without knowing what each terminal of the relay is. The present invention includes easy to use and intuitive controls and can quickly test 4-terminal or 5-terminal relays, giving a clear indication when such relays successfully pass or fail the test. The present invention is relatively easy to use with a vehicle battery or an on-board battery. Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

Drawings

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a cross-sectional view of the present invention electrically connected to a relay under test;

FIG. 3 is a schematic diagram of one embodiment of the present invention;

FIG. 4 is a flow chart for a 4-terminal relay showing the testing steps of the present invention;

and

fig. 5 is a flow chart for a 5-terminal relay showing the testing process of the present invention.

Detailed description illustrative embodiments of the invention are described below. The following description provides specific details for a thorough understanding and enabling description of these embodiments. It will be understood by those skilled in the art that the present invention may be practiced without these details. In other instances, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

Throughout the specification and claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, unless the context clearly requires otherwise; that is, it means "including but not limited to". Words using the singular or plural number also include the plural or singular number, respectively. Additionally, as used in this application, the words "herein," "above," "below," and words of similar import shall refer to this application as a whole and not to any particular portions of this application. When the claims use the word "or" to reference a list of two or more items, that word covers all of the following interpretations of the word: any item in the list, all items in the list, and combinations of items in any list. When the word "each" is used to denote at least one element previously described, the word "each" does not necessarily mean a plurality of elements, but may also mean a single element.

Fig. 1 and 2 show a tester 10 for a relay 20 of the type having four or five

electrical terminals

21, 22, 23, 28, 29, two

electrical terminals

21, 22 being

coil terminals

21, 22 connected on opposite sides of a relay coil 26, a single normally open terminal 28 or a single normally closed terminal 29, or a normally open terminal 28 and a normally closed terminal 29, and an armature terminal 23 electrically connected to an electrically conductive relay armature 27, if any, with the normally closed terminal 29 when the coil 26 is in a de-energized state 30, or with the normally open terminal 28 when the coil 26 is in an energized state 31. Such a relay 20 is either a 4-terminal normally open relay 20, a 4-terminal normally closed relay 20, or a 5-terminal relay having a normally open terminal 28 and a normally closed terminal 29, typically for use in a vehicle (not shown).

The test meter 10 includes a housing 40 and a circuit board 50 at least partially secured within the housing 40. Circuit board 50 includes a test circuit 60, test circuit 60 including a controller 61, two or more electronic switch components 70, a power supply 80, at least one indicator 90, a test enable switch 100, a relay-type switch 110, at least five voltage dividers 130, at least five analog-to-digital converters 140, and five electrical leads 120, each terminating at a distal end 128 thereof and having a conductive clip 129.

The housing 10 is preferably made of a rigid or semi-rigid material, such as injection molded plastic, metal, wood, or the like. The controller 61 is preferably an MCU such as the PIC16F18344 of microchip technology that is programmable to perform the testing steps and includes at least five analog-to-digital converters 140. The electronic switching component 70 is preferably a transistor assembly such as texas instruments ULN 2003A.

In one embodiment, power source 80 is a battery 81, an A/C adapter plugged into a 110V receptacle, or the like contained in housing 40, housing 40 being selectively sealable to retain battery 81 therein to have a removable door. Alternatively, the power supply 80 is an external power supply 82 having a positive power supply lead 83 and a negative power supply lead 84, each of which is connected to the test circuit 60 to power the test circuit 60 and the relay coil 26. The external power source 82, e.g., the vehicle battery 82, and the relay 20 are preferably from the same vehicle if the relay 20 under test is designed for such a vehicle so that it is safe to know the supply voltage VS of the vehicle battery 82 for powering the vehicle relay 20.

In some embodiments, at least the indicator 90 includes a green LED91 to indicate a pass of the relay test 170 and a red LED 92 to indicate a failure of the relay test 180. In some embodiments, at least one indicator 90 includes a 4-terminal LED 93 to indicate that the relay-type switch 110 is set to the first position 111 and a 5-terminal LED 94 to indicate that the relay-type switch 110 is set to the second position 112.

Test enable switch 100 is preferably a momentary contact normally open button or switch 100 and relay type switch 110 is preferably a two-position rocker type switch 110.

Due to the "pull-in time lag" of the relay, where the armature 27 does not move immediately when the state of the relay coil 26 changes, the controller 61 is adapted to perform a fast count of the number of electrical leads 120 that are grounded due to grounding one of the leads 120 before the relay 20 changes state. The controller 61 is also adapted to perform an alternating slow count of the number of electrical leads 120 that are grounded as a result of setting one of the leads 120 to ground, waiting until after the armature movement time once the relay 20 changes state.

Preferably, the test circuit 60 also includes a voltage regulator 190 (FIG. 3) for providing a component voltage V +, such as 5 volts, to the test circuit 60 when the voltage of the power supply 80 is higher than the component voltage V +. A diode bridge (not shown) may also be added to correct the polarity of the component voltages if the power leads 83, 84 are inadvertently connected to the wrong side of the external power supply 82. Alternatively, a diode D6 may be included to simply prevent the test circuit from operating if the power leads 83, 84 are inadvertently connected to the wrong side of the external power supply 82. In some embodiments, the resistors R1-R15 may be varied to accommodate external power sources 82 having 24 volts, or 12 volts, etc. In some embodiments, when the external power source 82 is connected to the test circuit 60, the test circuit 60 may measure the voltage of the external power source 82 and automatically switch a test voltage relay (not shown) between, for example, 12V and 24V. The voltage regulator 190 may include an additional switch (not shown) and additional circuitry with different resistors R1-R15, switched by a relay, so that the battery voltage of the external power source 82 may be selected by activating the additional switch.

Preferably, once the controller 61 determines which electrical lead 120 is connected to the relay coil 26, the controller 61 is adapted to run a predetermined number of cyclical relay tests 210, for example 10 times, to check for intermittent faults. Thus, if each of the cycling relay tests 210 passes, the controller 61 lights the green LED91, or if any cycling relay test 210 fails, the controller 61 lights the red LED 92.

In use, each

electrical terminal

21, 22, 23, 28, 29 of the relay 20 is connected to one of the leads 120 of the test circuit 60, and the relay-type switch 110 is set to the type of relay 20 being tested, and, with the test enable switch 100 enabled, the controller 61 may set each electrical lead 120 to ground in turn, and then count the number of the resulting other leads 120 that are grounded. The controller 61 then illuminates at least one indicator 90 to indicate a passing relay test 170 or a failing relay test 180 based on the measured count.

Specifically, for a 4-terminal type relay 20, the following steps are taken to test the relay 20 (fig. 4):

1. a test meter 10 as described above is provided.

2. Each

electrical terminal

21, 22, 23, 28 of the relay 20 is connected to one of the five electrical leads 120 of the test circuit 60. It does not matter which of the four electrical leads 120 is connected to each terminal 21, 22, 23, 28, simplifying the setup for the relay test.

3. The relay type switch 110 is set to the first position to indicate the 4-terminal type relay 20 being tested.

4. The supply voltage VS is applied to the test circuit 60, whereby each lead 120 is connected to the supply voltage VS.

5. The test enable switch 100 is activated.

6. The test circuit 60 then performs a test to ensure that the voltage of the power supply 80, and in particular if the voltage of the external power supply 82 connected to the test circuit 60 is within a preset appropriate voltage range, for example about 12-15.5V. If not, the test circuit 60 lights at least one indicator 90 to indicate a voltage fault condition, such as by flashing a red LED 92, and stops the test.

7. The test circuit 60 then performs a first round of testing by grounding the first electrical lead 120 and waiting for at least a predetermined armature movement time, such as one second.

8. The test circuit 60 then grounds each of the other electrical leads 120 in turn and quickly counts the number of leads 120 that are grounded. Test circuit 60 then adds each count to determine if the count is 10 and, if so, jumps to step 10.

9. The test circuit 60 then repeats step 7 in the next round of testing by grounding the next electrical lead 122, and so on until all five electrical leads 120 have been so grounded.

10. If no test run results count is 10, the test circuit 60 sets the red LED 92 to the relay test 180 indicating a failure and stops the test.

11. In some embodiments, the cycling relay test 210 is performed at this time, as will be described below.

12. If step 12 is reached, the test circuit 60 sets the green LED91 to indicate that the relay test 170 is passed.

In a normally operating relay 20, all

terminals

21, 22, 23, 27, 28 are set to VS, which will show the following results:

any number other than the count 10 indicates some type of fault in the relay 20.

The cyclical relay test 210 tests the cycle of electrical conductivity or resistance between the armature terminal 23, the normally open terminal 28, and the normally closed terminal 29, if present, for a predetermined number of times the relay 20 is energized and then the relay 20 is de-energized. Once the electrical leads 120 connected to the relay coil 26 are determined, a cyclical relay test 210 can be performed. In the above steps, any test run that results in a count of 10 ensures that two ground leads 120 are connected to the coil 26. In this way, the conductivity or resistance between the armature terminal 23 and the normally open terminal 28 can be tested when energizing and de-energizing the coil 26 and by setting the electrical lead 120 corresponding to the armature terminal 23 to ground. Similarly, when the coil 26 is energized and de-energized and by setting the electrical lead 120 corresponding to the armature terminal 23 to ground, the conductivity or resistance between the armature terminal 23 and the normally closed terminal 29, if present, can be tested. With the relay coil 26 in the energized state, the normally open terminal 28 in the relay 20 in operation will initially be disconnected from the armature 27 and will exhibit a zero voltage drop or substantially infinite resistance. Once the armature movement time has occurred and the relay 20 has changed state, the normally open terminal 28 of the relay 20 in operation will be electrically connected with the armature 27 and will show a voltage drop of the supply voltage VS, or substantially zero resistance. The relay 20 is repeatedly powered on and off and the remaining leads 120 are tested accordingly to ensure that the relay 20 is functioning properly. If any of the cycling relay tests 210 fails, the red LED 92 lights and the test stops. Otherwise, the green LED91 is illuminated to indicate that the relay test 170 is passed.

For a 5-terminal type relay 20, the relay 20 (fig. 5) is tested by the following steps:

1. a test meter 10 as described above is provided.

2. Each

electrical terminal

21, 22, 23, 28, 29 of the relay 20 is connected to one of five electrical leads 120 of the test circuit 60. It does not matter which of the five electrical leads 120 is connected to each terminal 21, 22, 23, 28, 29, simplifying the setup for the relay test.

3. The relay type switch 110 is set to the second position to indicate the 5-terminal type relay 20.

4. A supply voltage VS is applied to the test circuit 60, whereby each lead 120 is connected to the supply voltage VS.

5. The test enable switch 100 is activated.

6. The test circuit 60 then performs a test to ensure that the voltage of the power supply 80, and in particular the external power supply 82, is within a predetermined suitable voltage range, for example about 12-15.5V, if it is connected to the test circuit 60. If not, the test c1 circuit 60 lights at least one indicator 90 to indicate a voltage fault condition, such as by flashing a red LED 92, and stops the test.

7. The test circuit 60 performs a normally-closed test by grounding the first electrical lead 120 to ground and quickly counting the number of leads that are grounded. If the count is 2, the controller 61 jumps to step 10.

8. The normally closed test is repeated with the next electrical lead 120.

9. If all of the electrical leads 120 have been grounded in the normally closed test and have not counted as 2, the test circuit 60 sets the red LED 92 to the relay test 180 indicating a failure and the test stops.

10. The two electrical leads found to be grounded in the normally closed test are referred to as normally closed leads 23, 29.

11. The test circuit 60 now tests whether the normally closed leads 23, 29 are now open by grounding the remaining three electrical leads 120 instead of grounding the normally closed leads 23, 29 to search for the coil 26. If so, the ground leads are coil leads 21, 22, and if any of the remaining two leads 120 are connected to either of the normally closed leads 23, 29, then the two connected leads are normally open leads 23, 28. The common lead between normally closed leads 23, 29 and normally open leads 23, 28 is designated armature lead 23. The test circuit 60 jumps to step 13.

12. If the normally closed leads 23, 29 are never opened during step 11, the test circuit 60 sets the red LED 92 to indicate a failed relay test 180 and the test stops.

13. In some embodiments, a cyclical relay test 210 is performed at this time, as previously described.

14. A green LED91 is provided to indicate that the relay test 170 is passed and the test is stopped.

When it is determined whether the electrical terminal 23 connected to the armature 27 is in electrical contact with, for example, the normally closed terminal 29, the analog-to-digital converter 140 converts the voltage drop across the

terminals

23, 29 to see if it reads substantially zero volts. However, there may be a slight resistance between the

terminals

23, 29 due to contact wear and carbon build-up (not shown) on the contacts in the relay 20, in which case the voltage read at the normally closed contact 29 may be slightly above zero volts. In this way, the test threshold voltage Vc can be set such that resistances exceeding a certain value cause test failures even if they are but as if the

terminals

23, 29 were not in electrical contact, but due to contact carbon build-up.

While particular forms of the invention have been illustrated and described, it will be obvious that various modifications can be made without departing from the spirit and scope of the invention. For example, the shapes of the housing 40 and the circuit board 50 may be different from those shown in the figures. Accordingly, it is not intended that the invention be limited, except as by the appended claims.

Particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above detailed description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention.

The above detailed description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above or to the particular field of use mentioned in the present invention. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. Moreover, the teachings of the invention provided herein may be applied to other systems, not necessarily the systems described above. The components and acts of the various embodiments described above can be combined to provide further embodiments.

All of the above patents and applications, as well as other references, including any that may be listed in the accompanying application documents, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions and concepts of the various references described above to provide yet further embodiments of the invention.

Variations of the present invention are possible in light of the above detailed description. While the foregoing description details certain embodiments of the invention and describes the best mode contemplated, no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. Accordingly, implementation details may vary considerably while still being encompassed by the invention disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated.

While certain aspects of the invention are presented below in certain claim forms, the inventors contemplate the various aspects of the invention in any number of claim forms. Accordingly, the inventors reserve the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the invention.

Claims

1. A relay tester for use with four or five electrical terminals, two of which are coil terminals connected on opposite sides of a relay coil, one of which is an armature terminal electrically connected to a relay armature, and when the relay has four electrical terminals, the other of which is a single normally open terminal or a single normally closed terminal, and when the relay has five electrical terminals, the other two of which are a normally open terminal and a normally closed terminal, the relay armature being connected to the normally closed terminal when the coil is in a de-energized state, and the relay armature being connected to the normally open terminal when the coil is in an energized state;

the tester includes: a housing;

a circuit board at least partially secured within the housing, and the circuit board including a test circuit including a controller, two or more electronic switch assemblies, a power source, at least one indicator, a test enable switch, a relay type switch connected to the test circuit, the relay type switch having a first position for indicating a 4-terminal relay and a second position for indicating a 5-terminal relay, the test circuit further including five electrical leads, each electrical lead terminating at a conductive clip at a distal end thereof and including at least five voltage dividers and five analog-to-digital converters;

a test circuit provides power to each lead and is adapted to connect each of the five leads in turn to ground and measure the voltage between any two leads;

the controller is adapted to perform a fast count of the number of leads that have one lead grounded before the relay coil can change state, resulting in grounding, or a slow count of the number of leads that have been grounded after the armature movement time, where the relay has completely changed state, resulting in one lead grounded;

thus, each electrical terminal of the relay is connected to one lead of the test circuit, and the relay type switch is set to the relay type being tested, and upon activation of the test enable switch, the controller can set each lead to ground and then count the number of other leads that result in ground, the controller illuminating at least one indicator based on the measured count to indicate that the relay test passed or failed.

2. The tester of claim 1, wherein the test circuit further comprises a voltage regulator for providing a component voltage to the test circuit when the supply voltage is higher than the component voltage.

3. The tester of claim 2, wherein the component voltage is 5 volts.

4. The test meter of claim 1 wherein the at least one indicator comprises a green LED to indicate passing a relay test; and a red LED to indicate a relay test failure.

5. The test meter of claim 4 wherein the at least one indicator comprises a 4-terminal LED for indicating that the relay-type switch is set to the first position, and wherein the at least one indicator comprises a 5-terminal LED for indicating that the relay-type switch is set to the second position.

6. The test meter of claim 1 wherein the power source is a battery contained within the housing, the housing being selectively sealable to retain the battery therein.

7. The tester of claim 1, wherein the power supply is an external power supply, and wherein the test circuit includes a positive power supply lead connected to the test circuit and a negative power supply lead connected to the test circuit, the positive and negative power supply leads requiring connection to the external power supply prior to testing the relay.

8. The tester of claim 1, wherein once the controller determines which electrical lead is connected to the relay coil, the controller is adapted to run a predetermined number of cyclical relay tests, whereby the controller illuminates the at least one indicator to indicate a pass or failure of a relay test based on the results of the cyclical relay tests.

9. A method of testing a relay having four or five electrical terminals, two of which are coil terminals connected on opposite sides of a relay coil, one of which is an armature terminal electrically connected to a relay armature, the other of which is a single normally open terminal or a single normally closed terminal when the relay has four electrical terminals, the other two of which are a normally open terminal and a normally closed terminal when the relay has five electrical terminals, the relay armature being connected to the normally closed terminal when the coil is in a de-energized state, and the relay armature being connected to the normally open terminal when the coil is in an energized state, the method comprising the steps of:

providing a housing; a circuit board at least partially secured within the housing, and the circuit board including a test circuit including a controller, two or more electronic switch assemblies, a power source, at least one indicator, a test initiation switch, a relay type switch connected to the test circuit, the relay type switch having a first position for indicating a 4-terminal relay and a second position for indicating a 5-terminal relay, the test circuit further including five electrical leads, each electrical lead terminating at a conductive clip at a distal end thereof and including at least five voltage dividers and five analog-to-digital converters; a test circuit provides power to each lead and is adapted to connect each of the five leads in turn to ground and measure the voltage between any two leads; the controller is adapted to perform a fast count of the number of grounded leads resulting from grounding one lead before the relay coil changes state, or a slow count of the number of grounded leads resulting from grounding one lead after the relay coil changes state;

connecting each electrical terminal of the relay to one of five electrical leads of a test circuit, setting the relay type switch to the type of relay under test, and activating the test enable switch;

the test circuit tests to ensure that the supply voltage is within the appropriate voltage range and, if not, sets at least one indicator to indicate the absence of the appropriate input supply and stops the test;

connecting each electrical lead to a power supply

If the relay type switch is set to a 4-terminal relay, a 4-terminal relay test is performed as follows:

a1) performing a first round of testing by grounding the first electrical lead and waiting for at least a predetermined armature movement time;

b1) grounding each of the other electrical leads in turn and rapidly counting the number of grounded leads and adding each count to determine if the count is 10 and, if so, jumping to step d 1);

c1) repeating step a1 in the next round of testing by grounding the next electrical lead);

d1) if no test round has a result count of 10, the test circuit sets at least one indicator to indicate that the relay test failed and stops the test;

f1) setting at least one indicator to indicate that the relay test passes and stops the test;

if the relay type switch is set to a 5-terminal relay, a 5-terminal relay test is performed as follows:

a2) performing a normally closed test by grounding the first electrical lead and counting the number of grounded leads, and if 2, jumping to step d 2);

b2) repeating the normally closed test of step a2) by grounding the next electrical lead;

c2) if all the leads are tested in the normally closed test but none of the counts is 2, the test circuit sets at least one indicator to indicate that the relay test failed and stops the test;

d2) two grounded electrical leads are distributed as normally closed leads;

e2) searching for a coil by grounding the electrical leads of the remaining three normally closed leads that are not sequentially grounded, and after the armature movement time, testing whether the normally closed leads are open, if so, indicating the grounded lead as the coil lead, and if any of the remaining two leads is connected to any of the normally closed leads, if so, designating the two connected leads as the normally open lead, designating the normal lead between the normally closed lead and the normally open lead as the armature lead, and jumping to step h 2);

f2) the test circuit is provided with at least one indicator to indicate that the relay fails to test and stops testing;

h2) at least one indicator is provided to indicate that the relay test passed and stops testing.

10. The method of claim 9, further comprising the steps of:

e1) a cyclic relay test is performed for a predetermined number of cycles, comprising the steps of: deactivating the coil and grounding the armature leads to verify that the voltage drop across the normally open leads is sufficiently close to infinite, or, in the case of a normally closed relay, that the voltage drop across the normally open leads is sufficiently close to zero, and then activating the coil by grounding one of the coil leads and waiting for the armature movement time to verify that the voltage drop across the normally open leads is sufficiently close to zero, or, in the case of a normally closed relay, that the voltage drop across the normally closed leads is sufficiently close to infinite; thus, if any of the cycling relays test cycle fails, the test circuit lights at least one indicator to indicate the test failed and stops the test; and

g2) a cyclic relay test is performed for a predetermined number of cycles, comprising the steps of: deactivating the coils and setting the armature leads to ground, verifying that the voltage drop on the normally closed leads is close enough to zero, and the voltage drop on the normally open leads is close enough to infinite, by grounding one of the coil leads to activate the coil and wait for the armature movement time, verifying that the voltage drop on the normally closed leads is close enough to infinite and the voltage drop on the normally open leads is close enough to zero; thus, if any of the relay test cycles fails, the test circuit illuminates at least one indicator to indicate the test failed and stops the test;

said step e1) being between step d1) and step f 1);

said step g2) being between step f2) and step h 2).