Use PSSR to make light-controlled automatic flashing lights

The light-controlled automatic flashing light circuit made with PSSR is shown in Figure 3-65. The parameter solid-state relay PSSR
works in negative power driving mode in this circuit.
    KD-OIX is a single-chip soft-packaged integrated circuit. Its appearance is shown in Figure 3-66. Its working voltage is
1.35-5V, and its quiescent current is about 2uA. Pins 2 and 4 of the PSSR feed an operating current of about 3V and 2uA to the KD-OIX flashing integrated circuit
to keep it in normal working condition. Pin 2 of KD-OIX is the output terminal, which can output
square wave pulses with a frequency of about 1.2Hz (can be adjusted by the potentiometer RP). It has a load capacity of several mA, and RI and RP are its load resistors. When
its pin 2 outputs high level, no current flows through the load at this time, and the entire KD41X consumption is very small, much less than the output
current threshold value Jo of the PSSR. At this time, the PSSR works in the AB segment of the characteristic curve, and the 5 of the PSSR , the voltage drop of pin 6 U56 is very small, that is, PSSR
is in the open state, and the lamp H lights up; when pin 2 of KD-OIX outputs low level, hundreds of microamps of current flow
through the load resistor (RI+RP combined ), the quiescent current of KD-OIX is much larger than the feed-out current threshold, 0, and the PSSR works in
the CD section of the characteristic curve. At this time, U56 is equal to the power supply voltage 220V, that is, the PSSR is turned off and the lamp H goes out. From the above analysis
, it can be seen that the electric lamp H KD-OIX outputs a square wave frequency and flashes. The light control
part     of the circuit is completed by the photoresistor RG. The above analysis is based on the situation where the building is in a dark environment. Therefore, when RO is not illuminated by light, it shows high resistance (up to tens of megohms or more). Its connection is very important to the circuit. No impact. The situation is different during the day . At this time, RG is illuminated by light, and the resistance value quickly drops to several thousand ohms, making the feed current of pins 2 and 4 of PSSR much larger than the feed current threshold value, n. PSSR works in the CD segment, so Regardless of whether pin 2 of KD-OIX is high or low, PSSR is in the off state, and the light H is off.     The resistor R2 and capacitor C in the figure are absorption loops used to protect the PS SR parameter solid state relay.