JPS606985Y2 - Relay holding circuit - Google Patents

Description

[Detailed description of the invention] The present invention is a switch whose contacts are closed only during operation, and whose contacts open by self-returning when the operating force is released.
This invention relates to a relay holding circuit using a so-called momentary switch.

The first circuit operates a relay by operating a momentary switch once, closing the contacts, thereby energizing the load, and also self-holding the relay to continue energizing the load until the next momentary switch operation.
, as shown in Figure 2, is well known.

That is, in the conventional example shown in FIG. 1, S□ is a normally open momentary switch for driving a load, S2 is a normally open momentary switch for stopping the load, Q is a switching transistor, R is a relay having a normally open contact r1, and L is a normally open momentary switch for stopping the load. Load, R1,
R2 is a resistance.

When the switch S1 is now closed, the base current flows into the transistor Q1 via the resistor R1, so that the transistor Q□ is turned on.

As a result, relay R is energized, its contact r0 is closed, and the load is energized.

Since the base current continues to flow through the resistor B2 even after the switch S0 is opened, the relay R maintains its operating state.

In the next case of cancellation, when the switch S2 is closed, the base and emitter of the transistor Q1 are short-circuited, so that the transistor Q1 is turned off.

This cuts off the power to the relay R, opens the contact r, and cuts off the power to the load.

Further, in the conventional example shown in Fig. 2, Sl is a normally open momentary switch for driving a load, S3 is a normally open momentary switch for stopping the load, R is a relay having a normally open contact r1, and L is a normally open momentary switch for stopping the load.
is the load.

When the switch S□ is now closed, the relay R is energized and the load is also energized.

When the relay R is energized, its contact r1 is closed, and the relay R is self-held, and after the switch S1 is opened, the relay R is energized only by the contact r1.

Next, in the case of canceling, when switch S3 is opened, power to relay R is cut off, self-holding is canceled, and contact r□ is opened.

This also cuts off the power supply to the load.

By the way, in the conventional example described above, two momentary switches S1. S2 or S3
, which is not preferable because it makes the operation complicated and increases the cost.

In addition, in the conventional example shown in Fig. 2, the current to the load flows through the switch S until the contact r1 of the relay R closes, so the current capacity of the contact needs to be large. This is also undesirable as it increases costs.

Therefore, one possible method to achieve this using only one momentary switch is to use a circuit such as a flip-flop in J-, but this method also uses a circuit such as a flip-flop in CMO5J- as part of a large-scale system. There is no problem if a circuit is used, but if it is configured as an individual circuit, it still has the disadvantage of increasing costs.

The present invention was developed in view of the above points, and its purpose is to provide a relay holding circuit that uses one momentary switch and can turn on and off a relay with a simple circuit. It is in.

Next, an embodiment of the present invention will be described with reference to FIG.

S, is a normally open momentary switch, R is a relay with contact r, L is a load controlled by contact r, Q2
．． Q3 is the first. second switching transistor, C1
, C2 is the first. The second capacitor, R1-R5, is a resistor.

Next, to explain the operation, when the switch S4 is in the open state, the charges charged in the capacitors C1 and C2 are zero, so the charges of the transistors Q2. Q3 is in the off state.

When the switch S1 is closed, the charging current of the capacitor C□ flows to the resistor R□-capacitor C, -) transistor Q2.

The charging current turns transistor Q2 on, and
Relay R is activated and contact r1 of relay R is closed.

After the contact R is closed, the transistor Q3-resistor R3
The current that flows turns transistor Q3 on, and the current that flows from transistor Q3 to resistor R4 to transistor Q2 causes transistor Q2 to remain on even after capacitor C is fully charged, causing relay R to operate. Hold.

After the switch S is opened, the charge in the capacitor C□ flows through the capacitor C□, the resistor R2, and the resistor R6, and is discharged.

On the other hand, capacitor C2 - transistor Q3 - capacitor C
2 - Resistor R1 - Resistor 2 is charged by the current flowing through it, but as transistor Q3 continues to be in the on state, transistor Q2 also continues to be in the on state, so that relay R continues to be energized.

Next, when the switch S is closed for cancellation, the bases of the transistors are reverse biased due to the charge in the capacitor C2, and the transistor Q2 is turned off.

On the other hand, the capacitor C1 is charged by the current flowing through the resistor B1, the capacitor C1, and the transistor Q2, as in the case of setting, and only during this time, the transistor Q2 remains on.

By making the discharging time constant of the capacitor C2 longer than the charging time constant of the capacitor C1, the capacitor C1
When the charging current stops flowing, the base current of the transistor Q2, which flows through the transistor and the resistor R4, also stops flowing, so the transistor Q2 turns off.
Power to relay R is cut off and contact r1 is opened.

As mentioned above, the present invention can perform ON/OFF control of the relay with a single momentary switch, and has a simple circuit configuration, thereby reducing costs. Since this is the charging current of the capacitor which serves as the base current of the capacitor, the contact capacitance can be reduced, the degree of freedom in design can be increased, and the overall cost can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are circuit diagrams showing conventional relay holding circuits, and Figure 3 is a circuit diagram showing a conventional relay holding circuit.
The figure is a circuit diagram showing an embodiment of the relay holding circuit according to the present invention. S, Momentary switch, R...
・Relay, rl... Relay contact, Q2. Q3
・・・・・・First. Second transistor, C engineering, C2・
...1.12th capacitor, R□~R5...
···resistance.

Claims (1)

[Scope of utility model registration request] A normally open momentary switch, a first capacitor that is charged when the switch is closed, a first transistor that uses the charging current of the capacitor as a base current and controls a relay to be described later, and the transistor a second transistor to which power is supplied through the contacts of the relay and which supplies a base current to the transistor to form a self-holding circuit; and when the second transistor is in an on state; A relay holding circuit comprising: a second capacitor that is charged and provides a reverse bias to the base of the second transistor when the switch is closed again.