Touch electronic switch circuit design

The circuit working principle of this device is shown in Figure 2. TP is a touch metal piece. Usually, because a and b of TP are intermittent, it is equivalent to an open circuit between the ① and ② pins of LSE. Therefore, the ④ pin of LSE outputs a low level, and the relay J is in the released state, which is normally open. Contact j is disconnected and motor M does not work. When the finger connects the a and b segments on TP, the ④ pin of LSE has current output. At this time, the J excitation is closed, and its contact j is closed, turning on the power of the motor M, so the motor M runs. After releasing the hand, M stops working. TP can be made of copper-clad plate plated with silver.