WHAT ARE THE APPLICATIONS OF THE COUPLER

1. Switch circuit

When the input signal UI is low, the transistor V1 is in off state, a photoelectric coupler B1 current light emitting diode is approximately zero, the output of Q11 and Q12 between the high resistance, the equivalent switch is “off”; when UI is high, V1 conduction, B1 light-emitting diode, resistor Q11 Q12, the smaller, equivalent to the “on” switch. The circuit for Ui is low, so the high level switch barrier, conduction state. Similarly, because there is no signal (Ui low) when the switch is turned on, the low conducting state.

2. Composition logic circuit

Circuit and gate logic circuit. The logical expression for two photosensitive tube in P=A.B. series, only when the input logic level of A=1, B=1, P=1. output similarly, can also be composed of “gate” and “gate”, “or not” and other logic circuits.

3. Isolated coupled circuit

The circuit is shown in Figure 4. This is a typical AC coupled amplifier circuit. The current transfer ratio of B4 is a constant, and the linear amplification of the circuit can be guaranteed by the appropriate selection of the current limiting resistance Rl of the luminous circuit.

4. High voltage stabilized voltage circuit

The drive tube should adopt a high voltage resistance transistor (3DG27). When the output voltage increases, the bias of V55 increases, increasing the forward current of light emitting diode B5, the photodiode voltage decreases, adjusting pipe be junction bias voltage is reduced while the resistance increases, reduce the output voltage, and maintain the stable output voltage.

5. Automatic control circuit for lighting lamp

A is the four group analog electronic switch (S1~S4): S1, S2, S3 (parallel can increase the driving power and anti-jamming ability) for delay circuit, when the power is switched on after R4, B6 driven bidirectional thyristor VT, VT H S4 directly control the hall lights; and the external environment is composed of photosensitive resistance Rl light detection circuit. When the door is closed, mounted on the door frame of the normally closed type dry reed pipe by KD magnet on the door, the contact is broken, S1, S2, S3 in the open state data. Evening master home to open the door, the magnet away from the KD, KD contact closure. At 9V after R1 to C1 power rectifier charging, the voltage of C1 quickly increased to 9V, rectifier voltage by S1, S2, S3 and R4 make B6 LEDs to trigger bidirectional thyristor conduction, VT conduction, H lighting, automatic lighting control. After the door is closed, the magnet controls KD, the contact is disconnected, the 9V power is stopped to charge the C1, and the circuit is in a state of delay. C1 R3 began to discharge, after a period of time delay, the voltage of C1 decreased to S1, S2, open voltage S3 (1.5V), S1, S2, S3 back off, B6 VT also lead to deadline, deadline, H to achieve the function of delay lights out.