CD4013 remote control socket circuit

Recently, a friend's remote control socket could not cut off the power, so I asked the author to help repair it. After opening it, through inspection, it was found that the bidirectional thyristor had broken down. Troubleshooting after replacement. In order to facilitate readers to make their own or repair, the author has drawn the circuit as 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 receiving and processing, and socket power on and off. The principle is: when the remote control socket is inserted into the mains socket, the AC current is limited by C1, DL rectified, current limited again by R2, filtered by C2, and stabilized by W to obtain a voltage of about 10v. The voltage is current-limited by R3 and then added to the positive electrode of the red indicator light Q. After the bidirectional thyristor is turned on, because the collector of the control tube VT is low level, the red indicator light Q is lit, indicating that the remote control socket is powered. The other channel then gets a voltage of about 5 V after being stepped down by R6. This voltage passes through the inductor L and C4 to further filter out interference. It is used as power supply for the infrared receiving and processing integrated block IC1 (SFH505A) and is sent to its ① pin. The other power supply is used as a double D flip-flop IC2 (CD4013BP) to control the power on and off of the socket, and is directly sent to the ⑨ and (14) pins of Ic2. When the remote control control button is pressed, the infrared signal emitted by the remote control is received by Ic1. After internal shaping, amplification and decoding, a set of negative pulse signals is output from pin ③. As a result, the control tube VT1 is cut off and the collector becomes high level. That is, a positive pulse trigger signal is added to the input terminal (11) pin of the double D flip-flop Ic2 (see Figure 2 for the pin function of CD4013BP). Since the Ic2⑧ pin is Low level, pin ⑨ is high level, pin ⑩ is low level, as shown in the CD4013BP status table (see attached table)

It can be seen that the output terminal (13) pin should output a high level, that is, the input terminal ③ pin of the other unit of Ic2 is a high level. Since the ② pin (1) is connected to the ⑤ pin and is at a low level, the ④ and ⑥ pins are also at a low level because they are grounded. From the Ic2 state table, it can be seen that the output terminal is always opposite to the q level, that is, the ⑤ pin is always at the opposite level to the q level. ① The level of pin ① is opposite (when the cp terminal is triggered by a positive pulse, the q terminal and d terminal are always at the same level). Therefore, after the Ic2 ③ pin is triggered by a positive pulse, the 1q terminal must have the same level as the 1d terminal. Flip. Therefore, terminal 1q 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 to work. Once the 1q terminal flips, the level of the 1 terminal (that is, the 1d terminal) also flips, which is still opposite to the 1q terminal. Therefore, when the 1cp terminal is triggered again, the level of the 1q terminal will still be flipped. Therefore, the 1q terminal will output a low level → the control tube VT2 is cut off (because VT2 is cut off and the collector is at a high level, the red indicator light Q is off) → the bidirectional transistor VH is turned off when the alternating current crosses zero → the socket CZ is disconnected Electricity → The electrical appliance on the outlet stopped working. ...The result is that every time the cp terminal is triggered, the level of the 1q terminal flips once. That is, every time you press the remote control control button, the remote control socket changes regularly: power on → power off → power on →…. In Figure 1, C5, C6, C7, R10, and R11 can make the control have a certain delay effect.