1. Composition 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. Component 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 coupling circuit

The circuit is shown in Figure 4, which is a typical AC coupled amplifier circuit, which can be used to determine the linear amplification effect of B4 by selecting the current limiting resistor Rl.

4. High voltage stabilizing circuit

The drive transistor needs to use a higher voltage transistor (Figure 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 of hall 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. The night master comes home to open the door, magnet away from 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 the KD, the contact is disconnected, the 9V power supply stops charging the C1, and the circuit enters the delayed state. 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.