In this short period of time, because the capacitance of C3 is much larger than that of C2, the potential at point B quickly rises to a high level (about 1V), while the potential at point A rises below 0.6V, so Q3 is not conductive, only Q2 is conductive, so point C is at a high level, Q5 is conductive, relay J operates, and its contacts J- 1 and J-2 are simultaneously attracted. At this time, even if the IR no longer receives the infrared signal, because the power supply provides bias to Q5 through R 1 1, Q5 remains connected and J continues to pull in, thus achieving the purpose of turning on the remote controller by short pressing. Let's analyze the process of remote shutdown. When the remote control button is pressed for more than 3s, IR outputs a low-level pulse, so that Q 1 outputs a high-level pulse, which is rectified by D 1 and sent to point A and point B for integration. Finally, the potential of A is greater than 1V, Q3 is on, D is high, Q4 is on, and C is low, which leads to Q5 turning off and J releasing. Press and hold the remote control buttons J- 1 and J-2 to turn it off. When the remote control button is released, the infrared ray no longer receives the infrared signal, C2 and C3 are discharged, Q2 and Q3 are turned off, and the circuit enters the waiting state again. Only by pressing the remote control button again, the circuit will act again and repeat the process of remote control starting.
When the infrared receiver is stationary, the signal terminal outputs a high level. At this time, pin 3 of the clock input terminal of the flip-flop does not send a pulse signal, and the D terminal of pin 2 is at a high level. The q terminal of pin 5 is low. The triac BCR 1 is not conductive and the light bulb is not lit. When the infrared receiver receives the infrared pulse signal from the transmitter, the infrared receiver will output the standard negative pulse coded signal. The pulse signal is sent from the signal terminal of the receiver to the third pin of the D flip-flop IC 1A (namely the clock output terminal cLK). The rising edge of the negative pulse signal causes the T flip flop to flip. At this time, the D terminals of the two pins are at low level, and the Q terminals of the five pins are at high level, and the triac turns on the bulb to light up. When the lights need to be turned off, press any key of the remote controller, and the receiving head outputs a negative pulse to pull the trigger again. At this time, the Q terminal of pin 5 is at low level, the bidirectional thyristor BCR 1 is not conductive, and the lights are turned off.
If the selected C 1 is too small, the state cannot be maintained after triggering. If C 1 is too large, it will lead to failure. 10-47F is generally preferred, and the electrolytic capacitor of 10aF is selected for C/kloc-0 in the figure. When the receiver receives the infrared pulse signal sent by the remote controller, the negative pulse output by the signal terminal is coupled to the Ic 12 pin through c2. IC 1 is a Schmitt trigger circuit connected by NE555. After being shaped by IC 1, the pulse signal is output from IC 1 pin, and coupled to the rising edge counting end of14c4017 pin clock and the control output ends Q0~Q9 of IC2 through C4, from Q0 to high level, and from all other static low levels to Q 1 high. At this time, the thyristor connected with Q 1 is turned on (not shown in the figure) to make the connected load work. When you press any key on the remote control again. When the grade is changed to Q2 high grade, everything else is low grade, and only the load connected with Q2 works. If you continue to press any key of the remote controller, the control output will be executed in the above order.