JPH0522987Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a timer device that is driven by a power source whose voltage is lowered by step-down impedance, and whose output relay is operated by a time limit circuit.

[Conventional technology]

A timer device shown in FIG. 3 is known as a timer device that is driven by lowering a relatively high power supply voltage using a step-down impedance. Here, the timer circuit 1 connects a DC power supply 2 to a switch 3 and two step-down resistors 4 and 5.
connected to supply power through a series circuit. The output relay 6 is connected in series with the collector and emitter of the output transistor 7 and has both step-down resistors 4 and 5.
The base of this transistor 7 is connected to the output terminal of the timer circuit 1.

When switch 3 is turned on, timer circuit 1 starts,
After a predetermined period of time has elapsed from the start of time measurement, the time limit circuit 1 outputs a time-up signal and turns on the transistor 7, so that the output relay 6 operates.

[Problem that the invention attempts to solve]

This timer device uses a relatively high voltage DC power source 2.
is stepped down by both step-down resistors 4 and 5 and applied to the timer circuit 1 to drive it. For this reason, the voltage fluctuation rate is high, and when the time limit circuit 1 times up and turns on the transistor 7, causing an exciting current to flow through the coil of the output relay 6, the voltage drop across the resistor 4 becomes high, making it impossible for sufficient current to flow through the time limit circuit 1. There was a problem that the operation of the timer circuit 1 became unstable. In order to stabilize the operation of this timer circuit 1, the resistance value of the resistor 5 can be lowered to supply a sufficient current to the timer circuit 1, but if this is done, the current flowing through the resistor 4 becomes large, and this resistance There was a problem in that the heat generated by No. 4 accelerated the deterioration of the electronic components constituting the timer device, impairing the reliability of the timer device.

The purpose of the present invention is to provide a highly reliable timer device that supplies a stable current to a timer circuit regardless of whether the timer circuit times up, has low current consumption, and has little thermal deterioration of electronic components. .

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention is equipped with a timer circuit that measures time, an output transistor that is turned on by the output of this timer circuit, and an output relay that is activated when this output transistor is turned on. a first transistor whose collector-emitter is connected in series with the output relay and whose base is connected to the collector via a resistor; the output relay is connected in series with the time limit circuit; and a second transistor having a collector connected to the base of the first transistor, an emitter connected to a connection point between the output relay and the time limit circuit, and a base connected to the collector of the output transistor. .

[Effect]

The output relay is connected in series with the timer circuit to turn off the first transistor while the timer circuit is counting time, thereby preventing the output relay connected in series with the first transistor from operating. At this time, the timer circuit is operated to measure time via the second transistor and a resistor connected in series with the second transistor. When the timer circuit times out and the output transistor turns on, the second transistor turns off and the first
transistor turns on and energizes the timer circuit via the output relay.

〔Example〕

1 and 2 show an embodiment of a timer device according to the present invention, and the same parts as in FIG. 3 are given the same reference numerals as in FIG. 3. In FIG. 1, a time limit circuit 1 is connected to supply power from a DC power supply 2 through a series circuit including a switch 3, a step-down circuit including a step-down resistor 4, the collector/emitter of a transistor 8, and an output relay 6 when a time-out occurs. There is. The base of transistor 8 is connected to the collector via resistor 9. The collector of the transistor 10 is connected to the base of the transistor 8, the emitter is connected to the connection point between the output relay 6 and the time limit circuit 1, and the base is connected to the collector of the transistor 8 via a resistor 11. The output transistor 7 has a collector connected to the base of the transistor 10, an emitter connected to the negative terminal of the power supply 2, and a base connected to the output terminal of the time limit circuit 1. The resistance value of the resistor 9 is made equal to the resistance value of the coil of the relay 6, and the resistor 11 is approximately equal to the resistance value of the transistor 10 of the resistor 9.
The resistance value is multiplied by the current amplification factor.

When the switch 3 is turned on, the signal from the timer circuit 1 is at a low level and the transistor 7 is off, so a base current flows through the transistor 10 via the resistor 11, turning the transistor 10 on. When the transistor 10 is on, the base and emitter of the transistor 8 are short-circuited by the transistor 10 and the relay 6, so that the transistor 8 remains off. Therefore, power is supplied to the timer circuit 1 from the power supply 2 via the switch 3, the resistor 4, the resistor 9, and the transistor 10, and the timer circuit 1 is started and starts measuring time. Since the transistor 10 is selected to have a sufficiently large current amplification factor, the resistor 11 whose resistance value is approximately twice the current amplification factor of the transistor 10 as the resistance value of the resistor 9 is selected.
is a sufficiently high resistance value, and this current can be ignored. Therefore, the current consumption of the timer device at this time is determined by the voltage of the power supply 2, the resistance values of both resistors 4 and 9, and the equivalent resistance value of the timer circuit 1.

When the time limit circuit 1 times out after a predetermined time,
Transistor 7 is turned on and the base current of transistor 10 is short-circuited, so transistor 10 is turned off, base current flows to transistor 8 via resistor 9, and transistor 8 is turned on. When the transistor 8 is turned on, the timer circuit 1 is connected to the series power supply 2.
Power is supplied from the switch 3, the resistor 4, the transistor 8, and the relay 6, and the relay 6 operates. The current consumption of the timer device at this time is resistor 4,
It is determined by each resistance value of the relay 6 and the equivalent resistance value of the time limit circuit 1, and since the resistance value of the resistor 9 is made equal to the resistance value of the coil of the relay 6, the time limit circuit 1
The current value of the timer device when measuring time and when time-up is approximately equal, and the timer device operates stably. Moreover, since the same current flows in series through the relay 6 and the time limit circuit 1, the current consumption of the timer device is reduced compared to the conventional example. Although this embodiment has been described assuming that the current of the relay 6 and the current of the time limit circuit 1 are the same value, in general, the current of the time limit circuit 1 is often lower than the coil current of the relay 6. . In such a case, a bypass circuit may be provided in parallel with the timer circuit 1 so that the current value of the relay 6 and the sum of the current values of the timer circuit 1 and the bypass circuit are equal.

FIG. 2 shows an embodiment different from FIG. 1. This embodiment differs from FIG. 1 in that the power source is an AC power source 2a.
In this case, a rectifier circuit 12 and a smoothing circuit 13 are added immediately after the step-down resistor 4, and an AC timer device is formed. Other connections and operations are the same as those shown in FIG. 1, so their explanation will be omitted.

[Effect of idea]

According to the present invention, since the output relay is connected in series with the timer circuit, current consumption is reduced when the timer circuit times out. Therefore, the temperature rise of the step-down resistor is reduced, and the risk of thermal deterioration of electronic components is eliminated. When the timer circuit is measuring time, the second
transistor and a resistor connected in series with this second transistor, and when the timer circuit times out, the second transistor is turned off and the first transistor is turned on, and the coil of the output relay is Since the resistor and the resistor connected in series with the second transistor have approximately the same resistance value, the current consumption of the timer device is approximately the same both during time measurement and after time-up, and the timer device has the effect of stable operation.

[Brief explanation of the drawing]

1 and 2 respectively relate to a timer device according to the present invention, FIG. 1 is a circuit diagram showing one embodiment thereof, FIG. 2 is a circuit diagram showing a different embodiment from FIG. 1, and FIG. 3 is a conventional circuit diagram. FIG. 2 is a circuit diagram showing an example of a timer device. 1... Time limit circuit, 2, 2a... Power source, 4... Step-down resistor, 6... Output relay, 7... Output transistor, 8, 10... Transistor.

Claims (1)

[Scope of utility model registration request] A timer device comprising a timer circuit that measures time, an output transistor that is turned on by the output of the timer circuit, and an output relay that is activated when the output transistor is turned on, and is driven by a power source via a step-down impedance, wherein the output relay is A first circuit connected in series with the timer circuit, a collector emitter connected in series with the output relay, and a base connected to the collector via a resistor.
A transistor and a collector are connected to the base of the first transistor, an emitter is connected to a connection point between the output relay and the timer circuit, and a base is connected to the collector of the output transistor and the collector of the first transistor through a resistor. A timer device comprising: a second transistor connected to a second transistor;