DE3122841A1

DE3122841A1 - Electrical test instrument

Info

Publication number: DE3122841A1
Application number: DE19813122841
Authority: DE
Inventors: Hubertus 5948 Schmallenberg Schauerte
Original assignee: ARENS WOLFGANG
Current assignee: ARENS WOLFGANG
Priority date: 1981-03-10
Filing date: 1981-06-09
Publication date: 1983-01-05

Abstract

The electrical test instrument has a test probe, a key (A) and a light-emitting diode display for checking phase, neutral conductor, earth conductor, induction voltage and electrical components. The test probe is in each case brought into contact with phase, neutral or earth conductor during the test of the mains voltage. In this test, the presence or non-presence of phase, neutral and earth conductor is distinguished by the different indication of the light-emitting diode by contacting or not contacting the key (A). In the case of an induction voltage which is radiated by a mains cable through which current flows, the light-emitting diode display indicates the presence or, in the case of interruption, the non-presence when the probe tip is moved along the mains cable (see Table I). Table II shows how testing is carried out by continuity in the case of resistance and how the time constant (T) is tested in the case of the capacitor. By changing polarity, forward and reverse direction are determined in diode and transistor and the polarity in the case of the battery. One terminal of the electrical component is taken into one's hand whilst the probe tip is applied to the second terminal while simultaneously contacting the key (A) with the other hand. <IMAGE>

Description

B. Patentbeschreibung:B. Patent description:

Die Erfindung betrifft ein Prüfgerät, das im wesentlichen aus einer elektrischen Gleichspannungsquelle, einer Verstärkerstufe, einem Taster, einem Kondensator, einer Diode, zwei hochohmigen Widerständen, einer nach außen führenden flexiblen metallischen Prüfspitze und einer Leuchtdiodenanzeige besteht. The invention relates to a test device, which consists essentially of a electrical DC voltage source, an amplifier stage, a button, a capacitor, a diode, two high-ohmic resistors, a flexible one leading to the outside metallic test probe and an LED display.

Indem die flexible Prüfspitze an das zu überprüfende Objekt angelegt wird und gleichzeitig der menschliche Körper. den Taster berührt, wird ein äußerer Stromkreis gebildet und Je nach Prüfungsart geschlossen oder zur Erde kurzgeschlossen. Das Verhalten des äußeren Stromkreises wird durch die Anzeige der Leuchtdiode wiedergegeben, C. Anwendungsgebiete: Das Prüfgerät ist geeignet zur Überprüfung von Elektrobauteilen und Spannungen. Im einzelnen: (1) Widerstände / Leiter; Überprüfung auf Durchgang oder Nichtdurchgang. By placing the flexible test tip on the object to be checked becomes and at the same time the human body. touches the button, becomes an external one Circuit formed and, depending on the type of test, closed or short-circuited to earth. The behavior of the external circuit is shown by the display of the light-emitting diode, C. Areas of application: The test device is suitable for checking electrical components and tensions. In detail: (1) resistors / conductors; Check for continuity or non-passage.

(2) Halbleiter, Dioden, Transistoren; Feststellung der Durchgangs- bzw. Sperrichtung der Halbleiterzonen, (3) Kondensatoren; Überprüfung auf Kurzschluß bzw. des Kapazitätsbereiches. (2) semiconductors, diodes, transistors; Determination of the transit or reverse direction of the semiconductor zones, (3) capacitors; Check for short circuit or the capacity range.

(4) Primär- oder Sekunaär-Gleichspannungselemente; Feststellung der Polarität. (4) primary or secondary DC voltage elements; Finding the Polarity.

(5) überprüfung von Wechselspannungen im 220V-Bereich. (5) Checking AC voltages in the 220V range.

(Phase, Null, Erde). (Phase, zero, earth).

(6) Feststellung und Unterseheidung, ob Netz- oder Induktionsspannung vorhanden ist. (6) Determination and distinction, whether mains or induction voltage is available.

(7) Überprüfung eines isolierten Leiters, der 220 V-Wechselstrom führt, auf eine Unterbrechung und Lokalisierung einer etwaigen Unterbrechungsstelle. (7) Checking an insulated conductor that is 220 VAC leads to an interruption and localization of a possible interruption point.

D. Zweck: Das Prüfgerät kann in den genannten Anvendungsbereichen vom Elektrotechniker, aber auch vom Hobbyelektrotechniker eingesetzt werden. Wegen seiner vielseitigen Einsetzbarkeit erübrigt es dem Technikers verschiedene andere - und in aller Regel grube n - Prüfgeräte bei sich zu führen.D. Purpose: The test device can be used in the named areas of application can be used by electrical engineers, but also by amateur electrical engineers. Because Its versatility makes it unnecessary for the technician to have various other options - and as a rule pit n - to carry test devices with you.

E. Stand der Technik: Elektrische Prüfgeräte wie Durchgangsprüfer oder Spannungsprüfer kombiniert mit Durchgangsprüfer und Gliinmprüfer ( = Prüfstift ) sind in vielfältigen Ausführungen handelsüblich.E. State of the art: electrical test equipment such as continuity testers or voltage tester combined with continuity tester and contact tester (= test pin ) are available in various designs.

F. Kritik des Standes der Technik: Elektrisches Prüfgeräte zur überprüfung von Wechselspannungen im 220 V-Bereich sind heute noch in Form eines Duspols aufgebaut. Beim Duspol kann man durch verschiedenes Anlegen der beiden Prüfspitzen an einer Netzsteckdose feststellen, ob Phase, Null und Erde vorhanden sind. Zur unmittelbaren Feststellung der Phase ist in einem Duspol noch ein Glimmprüfer eingebaut.F. Criticism of the Prior Art: Electrical Test Equipment for Verification of alternating voltages in the 220 V range are still built up today in the form of a duspole. With the Duspol, you can apply the two test probes differently to one Determine the mains socket for phase, neutral and earth. To the immediate Determination of the phase there is also a glow tester in a Duspol built-in.

In den heutigen Spannungsprüfern, die vielfach kombiniert sind mit einem Durchgangsprüfer, aber den äußeren Aufbau eines Duspols aufweisen, fehlt der Glimmprüfer, der bei einem Duspol die unmittelbare Lokalisierung der Phase ermöglicht. Bei den beschriebenen Spannungsprüfern ist hingegen nur eine indirekte Prüfung der Phase möglich, indem man bei Anlegen der beiden Prüfspitzen an Null- und Erdleiter keine Spannung feststellt. Ein großer Nachteil ist auch, daß mit zwei Prüfspitzen gearbeitet werden muß und die Geräte unhandlich sind. Es gibt bis heute noch kein Prüfgerät, das handlich und von geringer Größe ist und mit nur einer Prüfspitze direkt die Phase, Null- und Erdleitung auf Vorhanden- oder Nichtvorhandensein überprüft, eine Induktionsspannung feststellen kann und bei Entlangführen der Prüfspitze an einem Wechselspannung führenden, isolierten Leiter die Induktionsspannung messen und bei etwaiger Unterbrechung im Leiter diese genau lokalisieren kann. In today's voltage testers, which are often combined with a continuity tester, but have the external structure of a Duspol, is missing Glow tester, which enables the immediate localization of the phase in the case of a duspole. In the case of the voltage testers described, however, only an indirect test is the Phase possible by applying the two test probes to the neutral and earth conductors detects no tension. Another major disadvantage is that it has two test probes must be worked and the devices are unwieldy. There is still none to this day Tester that is handy, small in size and with only one probe tip directly checks the phase, neutral and earth line for presence or absence, can detect an induction voltage and when the test probe is passed along Measure the induction voltage on an insulated conductor carrying AC voltage and can precisely locate any interruption in the conductor.

r. Aufhabe Der Erfindung liegt die Aufgabe zugrunde, verschiedene andere Prüfgeräte u ersetzen, dennoch klein und handlich zu sein, insbesondere nur eine Prüfspitze zu besitzen und bei Prüfungen von Elektrobauteilen die zweite Prüfspitze durch den menschlichen Körper zu ersetzen, damit der Prüfer das Prüfgerät bequem in eine Hand nehmen, dabei den Taster berühren und mit der anderen Hand das Elektrobauteil an einem der beiden Anschlüsse festhalten kann und die Prüfspitze des Prüfgerätes an den zweiten Anschluß des Bauteiles halten kann.r. Object of the invention is based on the object, various other test equipment u replace, nevertheless, to be small and handy, in particular only To have a test tip and the second test tip when testing electrical components by replacing it with the human body, so that the examiner can use the testing device conveniently in one hand, touch the button and the electrical component with the other hand can hold on to one of the two connections and the test probe of the test device can hold on to the second connection of the component.

H. Lösung: Diese Aufgaben werden erfindungsgemäß durch die im kennzeichnenden Teil der Ansprüche 1 bis 10 angegebenen Merkmale gelöst, I. Erzielbare Vorteile: Der mit der Erfindung zu erzielende Vorteil besteht darin, daß das Prüfgerät eine Vielzahl von unterschiedlichen Prüfungen ermöglicht. Es ist klein und handlich und benötigt keinen Schalter, der bei einem Prüfvorgang ein- und ausgeschaltet werden müßte. Das Prüfgerät besitzt eine steckbare handelsübliche 9-V-Flachp batterie, die Jederzeit problemlos ausgetauscht werden kann, weil das Prüfgerät direkt auf ihr aufgebaut ist.H. Solution: These tasks are solved according to the invention by the in the characterizing Part of the claims 1 to 10 specified features solved, I. Achievable advantages: The advantage to be achieved with the invention is that the tester has a Allows for a large number of different tests. It's small and handy as well does not require a switch to be switched on and off during a test process would have to. The test device has a plug-in, commercially available 9 V flat battery, which can be exchanged at any time without any problems, because the test device is directly on it is built up.

Es besitzt eine flexible metallische Prüfspitze, die durch ringförmiges Umlegen um einen unter Wechselspannung stehenden isolierten Leiter dessen abstrahlende Induktionsspannung auf das Prüfgerät verstärkt. Das Prüfgerät ist im schaltungstechnischen und äußeren Aufbau so konzipiert, daß es den menschlichen Körper auch vor Spannungen schützt, die die Netzwechselspannung um ein Vielfaches übersteigen, Das Prüfgerät benötigt nur eine Prüfspitze. Zur Überprüfung von Elektrobauteilen wird die zweite Prüfspitze durch den menschlichen Körper ersetzt, was eine große Erleichterung für den Techniker bedeutet, weil er in der einen Hand das Elektrobauteil und in der anderen das Prüfgerät halten kann. It has a flexible metallic test probe, which is ring-shaped Wrapping around an AC voltage insulated conductor of the radiating one Induction voltage amplified on the test device. The test device is in the circuitry and external structure designed so that it protects the human body from tension protects that exceed the mains alternating voltage many times over, the test device only requires one test probe. The second Test probe replaced by the human body, which is a great relief for means the technician because he has the electrical component in one hand and the others can hold the tester.

K. Ausführungsbeispiel: Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt.K. Embodiment: An embodiment of the invention is shown in the drawing.

Fig. 1 zeigt den schaltungstechnischen Aufbau, die Einsatzmöglichkeiten und die Handhabung zur über prüfung von Elektrobauteilen und Spannungen.Fig. 1 shows the circuit structure, the possible uses and the handling for checking electrical components and voltages.

Zum schaltungstechnischen Aufbau des Prüfgerätes gehört einmal die elektrische Gleichspannungsquelle (1), eine 9 V-Flachbatterie, deren Anschluß (= Kontakte (19) und (20) ) mit einem 12 mm-9 V-Flachstecker (26) verbunden sind. Der weitere Aufbau besteht aus einer hochwertigen Verstärkerstufe (2), einer Leuchtdiode (3), zwei hochohmigen Widerständen (4), (6), einer flexiblem metallischen Prüfspitze (7), einem Taster (23), einer Diode (5) und einem Kondensator (24), Fig. 1 zeigt die Einsatzmöglichkeiten und Handhabung bei der Überprüfung von Elektrobauteilen wie Gleichspannungselementen (9), Widerständen (wo), Dioden (li), Transistoren (12) und Kondensatoren (13). Ein Anschluß des Elektrobauteiles wird über den menschlichen Körper (8) mit der Taste (23) verbunden. Der zweite Anschluß des Elektrobauteiles wird dann mit der Prüfspitze (7) in Berührung gebraucht, so daß der äußere Stromkreis geschlossen ist. Dadurch gelangt das am Taster (23) anstehende positive Potential zum Eingang der Verstärkerstufe (2) und steuert diese durch.The circuit structure of the test device includes the electrical DC voltage source (1), a 9 V flat battery, the connection of which (= Contacts (19) and (20)) are connected with a 12 mm 9 V flat plug (26). Of the Another structure consists of a high-quality amplifier stage (2), a light-emitting diode (3), two high-value resistors (4), (6), a flexible metallic test probe (7), a button (23), a diode (5) and a capacitor (24), Fig. 1 shows the possible uses and handling when checking electrical components like DC voltage elements (9), resistors (wo), diodes (li), transistors (12) and capacitors (13). A connection of the electrical component is via the human Body (8) connected to the button (23). The second connection of the electrical component is then used with the test probe (7) in contact, so that the external circuit closed is. As a result, the positive potential at the button (23) is applied to the input of the amplifier stage (2) and controls it.

Bei der Überprüfung einer Netzsteckdose (15) wird Je nach Prüfungszweck die Prüfspitze (7) mit der Phase (16), dem Nulleiter (17) oder dem Erdleiter (18) in Verbindung gebracht. Ist bei der Phasenprüfung die Phase (16) der Netzsteckdose (15) nicht vorhanden, wird die Verstärkerstufe (2) nicht angesteuert. Ist die Phase vorhanden, so gelangt die Netzwechselspannung von der Prüfspitze (7) über den Widerstand (6) und Basis und Emitter der Verstärkerstute (2) zum negativen Pol (19) der Oleichspannungsquelle (1) ( = Batterie ). Die Netzwechselspannung wird über den inneren Kondensator (25) und die Ummantelung (28) der Batterie zur Erde (14) weiter geführt, weil die Ummantelung (28) der Batterie bei Jeder Prüfung durch den menschlichen Körper (8) mit der Erde (14) verbunden ist. Wegen dieser Verbindung entsteht ein größerer Spannungsabfall zwischen Basis und Emitter der Verstärkerstufe (2), wodurch sich die Verstärkung erhöht und die Leuchtdiode (3) heller aufleuchtet.When checking a mains socket (15), depending on the purpose of the test the test probe (7) with the phase (16), the neutral conductor (17) or the earth conductor (18) connected. Is the phase in the phase test (16) the mains socket (15) is not available, the amplifier stage (2) is not activated. If the phase is present, the mains alternating voltage comes from the test probe (7) via the resistor (6) and the base and emitter of the amplifier connector (2) to the negative Pole (19) of the DC voltage source (1) (= battery). The AC mains voltage is via the inner capacitor (25) and the casing (28) of the battery to earth (14) continued because the sheathing (28) of the battery passed through each time it was checked the human body (8) is connected to the earth (14). Because of this connection there is a larger voltage drop between the base and emitter of the amplifier stage (2), which increases the gain and the LED (3) lights up brighter.

Ist bei der Erdleiterprüfung die Erdung (18) der Netzsteckdose (15) nicht vorhanden, so wird durch die Phase (16) eine Induktionsspannung im Erdleiter (18) hervorgerufen. Diese Induktionsspannung führt zum gleichen Verstärkungsvorgang wie beschrieben für das Vorhandensein der Phase (16) bei der Phasenprüfung und bewirkt das gleiche Anzeigeverhalten. Phase (16) und Induktionsspannung im Erdleiter (18) können wie in Anspruch 2 beschrieben wurde, durch Berühren des Tasters (23) voneinander unterschieden werden. Ist Erdung (18) vorhanden, so ruft die Phase (16) keine Induktionsspannung im Erdleiter (18) hervor, so daß der Einfang der Verstärkerstufe (2) nicht angesteuert wird. Erst durch Berühren des Tasters (23) mit dem menschlichen Körper (8) gelangt das am Taster (23) vorhandene positive Potential über die Erde (14), den Erdpol (18), die Prüfspitze (7) und den Widerstand (6) zum Eingang der Verstärkersrufe (2). Da auch der Nulleiter (17) Erdpotential aufweist, ist die Nulleiterprüfung identisch mit der Erdleiterprüfung. Die Jeweils verschiedene Anzeige der Leuchtdiode (3) macht eine genaue Unterscheidung und Feststellung der Potentiale und der Phase (16), der Null-(17) und der Erdleitung (18) möglich. Zur Feststellung einer Unterbrechung in einem isolierten Leiter (22) führt man die flexible metallische Prüfspitze (7) an dem Leiter (22) entlang. Die Induktionsspannung wird von der Prüfspitze (7) aufgenommen und steuert die Verstärkerstufe (2) durch. Legt man einige Schleifen mit der flexiblen metallischen Prütspitze (7) um den Leiter (22), so wird die Induktionsspannung auf den Eingang der Verstärkerstufe (2) verstärkt. Bei einer Unterbrechung im Leiter (22) wird die Wechselspannung nicht mehr weitergeführt, es kann somit an der Unterbrechungsstelle auch keine Induktionsspannung abgestrahlt werden.During the earth conductor test, is the earth (18) of the mains socket (15) does not exist, phase (16) creates an induction voltage in the earth conductor (18). This induction voltage leads to the same amplification process as described for the presence of phase (16) in the phase test and effected the same display behavior. Phase (16) and induction voltage in the earth conductor (18) can as described in claim 2, by touching the button (23) from each other can be distinguished. If there is grounding (18), phase (16) does not generate any induction voltage in the earth conductor (18) so that the capture of the amplifier stage (2) is not activated will. Only reached by touching the button (23) with the human body (8) the positive potential on the button (23) via the earth (14), the earth pole (18), the test probe (7) and the resistor (6) to the input of the amplifier calls (2). Since the neutral conductor (17) also has earth potential, the neutral conductor test is required identical to the earth conductor test. Each different display of the light emitting diode (3) makes a precise distinction and determination of the potentials and the phase (16), the neutral (17) and the earth line (18) possible. To determine an interruption The flexible metallic test probe (7) is placed in an insulated conductor (22) along the conductor (22). The induction voltage is picked up by the test probe (7) and controls the amplifier stage (2). If you put some loops with the flexible metallic probe tip (7) around the conductor (22), so the induction voltage is on amplifies the input of the amplifier stage (2). In the event of a break in the conductor (22) the AC voltage is no longer carried on, so it can be at the point of interruption no induction voltage can be emitted either.

Die Versarkerstufe (2) wird dann nicht mehr angesteuert.The boost stage (2) is then no longer activated.

Durch das Anzeigeverhalten der Leuchtdiode (3) wird die Unterbrechungsstelle genau festgestellt.The point of interruption is determined by the display behavior of the light-emitting diode (3) precisely established.

Fig. 2 zeigt den äußeren Aufbau des Prüfgerätes. Die elektrische Gleichspannungsquelle (1) wird direkt über den 12 mm - 9V-Flachstecker (26) mit dem PrüfgerCitverbunden. Die Bestandteile des Prüfgerätes sind in einer hochisolierten Masse (27) eingegossen. Nach außen hin geführt ist die Leuchtdiode (3), der Taster (23) und die flexible metallische Prüfspitze (7) mit ihrer teilweisen Umhüllung aus isoliertem Material (21).Fig. 2 shows the external structure of the testing device. The electrical DC voltage source (1) is connected directly to the PrüfgerCit via the 12 mm - 9V flat plug (26). The components of the test device are cast in a highly insulated compound (27). The light-emitting diode (3), the button (23) and the flexible one are guided to the outside metallic test probe (7) with its partial covering made of insulated material (21).

Claims

Re: Patent application for an electrical test device A) Patent claims Electrical test device with LED display for detection and differentiation of induction and mains voltage in the 220 V range, testing of the polarity of direct voltages and electrical components (resistors, capacitors, diodes, transistors) from an electrical DC voltage source (1), a high-quality amplifier stage (2), which is constructed in a Darlington circuit, a flexible metallic one Test probe (7), a light-emitting diode display (3), a diode (5), a capacitor (24) and the high-value resistors (4), (6).

characterized in that a) that by applying the test probe (7) of the Connect the device to the phase (16) of a 22oV mains socket (15) the mains voltage (220 V) via a high-resistance resistor (6) to the input of the amplifier stage (2) so that the amplifier stage (2) is controlled and the light emitting diode (3) for display is brought.

characterized in that b) that by guiding the test probe along (7) on an insulated conductor (22) carrying 220 V alternating current the test probe (7) transmitted induction voltage via the high-value resistor (6) to the input of the amplifier stage (2) and this switches through, whereby the LED (3) is displayed will. The test probe (7) is made of flexible metal so it can be annular around the area to be checked Cable or the checking conductor (22) can be placed so that the on it transmitted- induction voltage is increased.

2) Electrical test device according to claim 1, characterized in that that the voltage applied to the test probe (7) (mains alternating voltage or induction voltage) as described in claim la and b, the light-emitting diode (3) displays over the capacitor (24), the high-resistance resistor (4) and the button (23), which through the human body (8) is touched, is short-circuited to earth.

The impedance of the amplifier stage (2) is dimensioned so that with induction voltage the remaining voltage at the input of the amplifier stage (2) due to the short circuit is no longer sufficient to control the amplifier stage (2) and the light-emitting diode (3) to be reported.

In contrast, the sensitivity of the amplifier stage (2) is dimensioned so that that when mains AC voltage (220 V) is applied, despite the short circuit with the Earth (14), the residual voltage still occurring at the input of the amplifier stage (2) The amplifier switches through and the LED (3) continues to display. Because of the different Display behavior, it is possible to distinguish or determine whether induction or AC voltage is present.

3) Electrical test device according to claim 1, characterized in that that the base of the input amplifier stage (2) via the high-resistance resistor (6), the test probe (7), the human body (8), the button (23), the high-resistance Resistor (4) and the diode (5) with the positive pole (20) of the electrical DC voltage source (1) is connected.

a) Electrical test device according to claim 1 and 3, characterized in that that, as described in claim 3, the DC voltage source to be checked (9) on the one hand with the test probe (7) and on the other hand via the button (23) with the human body (8) is connected. If the negative pole of the to be checked DC voltage source (9) is applied to the test probe (7) and accordingly the positive pole is connected to the button (23) via the human body (8), the base of the input amplifier stage is driven negatively, so that the amplifier stage (2) is not controlled and the LED (3) is not displayed. If, on the other hand, the positive pole of the DC voltage source (9) to be tested is present the test probe (7) and is the negative pole over the human body (8) connected to the button (23), the base of the input amplifier stage becomes positive controlled so that the amplifier stage (2) controls and the light emitting diode (3) is brought to the display. Due to the display or non-display of the light emitting diode (3) when the test probe (7) and the human body (8) are placed on the poles the DC voltage source (9) to be checked can thus determine the polarity of the DC voltage source (9) can be determined.

b) Electrical test device according to claim 1 and 3, characterized in that that, as described in claim 3, the resistance path to be checked (lo) (Resistance or conductor) on the one hand with the test probe (7) and on the other hand over the human body (8) is connected to the button (23). The amplifier stage (2) is dimensioned in such a way that only if the resistance path to be checked (lo) Has infinitely high impedance, the amplifier stage (2) no longer through the positive Pole (20) of the electrical DC voltage source (1) is controlled. Against it is even with very high impedances of the resistance path to be checked (io) die positive control of the base of the input amplifier stage is still sufficient to Control the amplifier stage (2) and the light-emitting diode (3) see full ad bring to. This means that continuity or non-continuity can be achieved even with very high resistance Resistance distances are determined.

c) Electrical test device according to claim 1 and 3, characterized in that that, as described in claim 3, the diode to be checked (11) on the one hand with the test probe (7) and on the other hand via the human body (8) with the button (23) is connected.

Is the diode to be checked (11) in the direction of passage between the positive pole (20) of the DC voltage source (1) and the base of the input amplifier stage included in the circuit, the amplifier stage (2) controls through and brings the light-emitting diode (3) to the display. If, on the other hand, the diode to be checked (11) included in the reverse direction in the circuit, as the diode (11) then represents an infinitely high resistance, the basis of the input amplifier stage not controlled by the positive pole (20) of the electrical DC voltage source (1), so that the light emitting diode (3) does not appear on the display. This allows through and reverse direction of a diode can be determined.

d) Electrical test device according to claim 1 and 3, characterized in that that, instead of a diode (11) according to claim 3 c), a p-n-p or n-p-n transistor (12) is inserted into the circuit in such a way that either through or blocking direction can be determined by base emitter, base collector or collector emitter.

e) Electrical test device according to claim 1 and 3, characterized in that that a capacitor (13) on the one hand to the test probe (7) and on the other hand over the human body (8) is connected to the button (23). By the capacitor (13) is so inserted into the circuit, the charging current flows to the base the input amplifier stage; the amplifier stage (2) controls through and the light emitting diode (3) comes to the display. When the charging process is completed, the capacitor controls (13) due to its polarity, the base of the input amplifier stage is negative and the LED display (3) goes out. The duration of the LED display (3) thus shows the charging time of the capacitor to be checked (13) and therefore indirectly its capacity.

4) Electrical test device according to claims 1, 2 and 3, characterized in that that the test probe (7) is placed on the earth pole (18) of a mains socket (15) (cf. Fig. 1).

a) First case: earth potential at the earth pole (18) present: only if there the button (23) is touched by the human body (8) and thus with the floor (= Earth (14) is connected, the LED (3) is displayed. The sensitivity the amplifier stage (2) is - as described in claim 3 b) - dimensioned so that despite the very high impedance of the resistance path resulting from the connection from the button (23) over the human body (8), the ground (= earth) (14) and the ground pole (18) to the test probe (7) results, the amplifier stage (2) is still controlled and the light emitting diode (3) is displayed.

b) Second case: Earth potential at the earth pole (18) does not exist: Because If there is no earth potential at the earth pole (18), the phase (16) calls an induction voltage in the earth pole (18). As a result, as described in claim 1, the light-emitting diode brought to the display. This induction voltage can then be derived from mains voltage a distinction is made that - as also described in claim 2 - when touching of the button (23) through the human body (8) the LED display (3) goes out.

5) Electrical test device according to claims 1, 2, 3, 4a and b, thereby characterized in that the test probe (7) is connected to the neutral conductor (17) of a 220 V mains socket (15) is applied. Since the neutral conductor (17) - like the earth pole (18) - earth potential the test device is as described in claim 4 a) 5 for determination the presence of the neutral conductor (17) or, as described in claim 4 b), for Determination of the absence of the neutral conductor (17) to be used.

6) Electrical test device according to claim 1, 4a and b, characterized in that that the electrical DC voltage source (1) (= 9 V flat battery) in the internal structure a capacitor (25) from the positive and negative pole to the jacket (28) of the Has battery. The external structure of the Pr-iitgerätes is constructed in such a way that at Each test process the casing (28) of the 9 V flat battery by the human Body (8) is touched. When an alternating or induction voltage is applied the test probe (7), this reaches the base and on via the resistor (6) the emitter of the amplifier connector (2) to the negative pole (19) of the electrical DC voltage source (1) = battery. The alternating or induction voltage will then continue to be silver inner capacitor (25) led to the casing (28) of the battery and is with the human body (8) in contact with the casing (28) connected to earth (14). This connection creates a greater voltage drop between the base and emitter of the amplifier stage (2), so that the amplifier stage (2) more and the LED () lights up brighter. Will be about the battery If a plastic housing is built, the inner capacitor (25) of the battery must through an externally connected capacitor can be replaced. This capacitor must with a connection to the positive or negative pole of the electrical DC voltage source be connected. The second terminal of the capacitor becomes a third Button (which replaces the casing (28) of the battery).

7) Electrical tester according to claim 1, 2, 3, 4, 5 and 6, characterized characterized in that the capacitor (24) has a DC coupling from the positive Pole (20) on the input of the amplifier stage (2) prevented. Because the capacitor (24) does not represent a resistance for the applied AC or induction voltage, can this - as described in claim 2 - from the input of the amplifier stage (2) get to the button (23) and by touching the button (23) with the human Body (8) are short-circuited to earth (14). The diode (5) blocks the positive Half-wave of the applied mains alternating or induction voltage and thus prevents that there is a current flow to the positive pole (20) of the DC voltage source (1) and comes via the inner capacitor (25) to the casing (28) of the battery and at Touching the casing (28) by the human body (8) in this way a short circuit to earth (14) takes place.

The positive half-wave of the alternating mains or induction voltage is present therefore so long at the input of the amplifier stage (2) until - as described in claim 2 - The short circuit to earth (14) by touching the button (23) with the human Body (8) takes place. The diode (5), however, is in the forward direction for the positive Pole (20) of the DC voltage source (1) connected potential, so that the The button (23) has a positive potential and so the one described in claim 3 Component tests can also be carried out.

8) Electrical test device according to claims 1,2,3,4,5,6 to to and Y, characterized in that due to the structure of the test device, it is the electrical DC voltage source (1) is only used when a test process according to claim 1, 2, 3, 4, 5, 6 or 7 is carried out, because only then the amplifier stage (2) is controlled, so that there is a flow of current that the light emitting diode (3) displays, This special structure makes it possible to use the test device to operate switchless.

9) Electrical tester according to claims 1,2,3,4,5,6,7 and 8, thereby characterized in that the electrical DC voltage source (1) is a commercially available 9 V flat battery is used. The other components of the test device are located on a 9 V flat plug (26), which by simply plugging it onto the poles (19) and (20) with the battery - electrical DC voltage source (1) - directly is connected, so that the dimensions of the device are kept optimally small and the battery can be changed without any problems (cf.Flg. 2).

10) Electrical test device according to claims 1, 2, 3, 4, 5, 6, 6, 8 and 9, characterized in that the attached to the 12 mm - 9 V flat plug (26) Components are cast in a highly insulated compound (27) and in the test device located resistors (4) and (6) are designed so high that when touched the button (23) or the battery - electrical DC voltage source (1) - through the human body (8) a hazard for this itself then excluded is when a voltage is applied to the test probe (7) that reduces the mains voltage by one Multiple exceeds (cf. Fig. 2). The test probe (7) is made of an insulated material (21) encased, only a small part at the upper end of the test probe (7) is not insulated, this ensures further protection for the human body (8).