CD4013 remote control socket circuit

Recently, a friend's remote control socket could not be powered off, so he asked me to help him repair it. After opening it, it was found that the bidirectional thyristor had broken down through testing. After replacing it, the fault was eliminated. In order to facilitate readers to make or repair it, I drew the circuit shown in Figure 1 based on the actual object (the circuit component numbers are noted by the author). The remote control socket is mainly composed of three circuits: power supply, infrared reception processing and socket power on and off. Its principle is: when the remote control socket is inserted into the mains socket, the AC power is limited by C1, rectified by DL, limited by R2 again, filtered by C2, and stabilized by W to obtain a voltage of about 10V. This voltage is limited by R3 and added to the positive electrode of the red indicator Q. After the bidirectional thyristor is turned on, the collector of the control tube VT is at a low level, so the red indicator Q is lit, indicating that the remote control socket has been powered. Another path is reduced by R6 to obtain a voltage of about 5 V. This voltage is further filtered out by inductor L and C4. It is used as the power supply for the infrared reception and processing integrated block IC1 (SFH505A) and sent to its ① foot. Another power supply of the dual D flip-flop IC2 (CD4013BP) used to control the power on and off of the socket is directly sent to the 9th and (14th) pins of IC2. When the remote control button is pressed, the infrared signal emitted by the remote control is received by IC1. After internal shaping, amplification, and decoding, a group of negative pulse signals are output from pin ③. Therefore, the control tube VT1 is cut off. The collector becomes high level. That is, a positive pulse trigger signal is added to the input terminal (11) pin of the dual D flip-flop IC2 (see Figure 2 for the pin function of CD4013BP). Since the ⑧ pin of IC2 is low level, the 9th pin is high level, and the ⑩ pin is low level, according to the CD4013BP state table (see the attached table)

It can be seen that its output terminal (13) pin should output a high level, that is, the input terminal of another unit of Ic2, pin 3, is a high level. Since pin 2 (1) is connected to pin 5 and is at a low level, pins 4 and 6 are also at a low level due to grounding. From the state table of Ic2, it can be seen that the output terminal is always opposite to the q level, that is, the 5th pin is always opposite to the 1st pin level. (When the cp end is triggered by a positive pulse, the q end and the d end are always at the same level). Therefore, after the cp end is triggered by a positive pulse, the 1q end must flip in order to have the same level as the 1d end. Therefore, the 1q end outputs a high level → the control tube VT2 is turned on → the bidirectional thyristor VH is triggered and turned on → the socket CZ is powered → the electrical appliances on the socket are powered and work. Once the 1q end flips, the level of the 1 end (i.e., the 1d end) also flips and is still opposite to the 1q end. Therefore, when the 1cp end is triggered again, the 1q end level will still flip. Therefore, the 1q terminal will output a low level → the control tube VT2 is cut off (because VT2 is cut off, the collector is high level, so the red indicator light Q is off) → the bidirectional thyristor VH is turned off when the AC power passes zero → the socket CZ loses power → the electrical appliances on the socket stop working. ... As a result, every time the cp terminal is triggered, the level of the 1q terminal flips once. That is, every time the remote control button is pressed, the remote control socket is powered on → power off → powered on → .... Regular changes. C5, C6, C7, R10, and R11 in Figure 1 can make the control have a certain delay effect.