Desk lamp touch switch circuit

desk lamp touch switch   　　

If you add an inductive touch switch to the desk lamp in your home, it will not only bring you fun when using it, but also make it more convenient for you to use. Working principle The circuit of this device is shown in Figure 1. When a human hand touches the metal contact piece A, the clutter signal on the human body is added to the ② pin of the time base circuit through C3. The ② pin is triggered, the entire flip-flop flips, and the ③ pin outputs a high level, and the output passes through the current limiting resistor R Added to the thyristor control electrode, the thyristor VS turns on and ZD lights up. When you need to turn off the light, touch the metal piece B with your hand. The induction signal is added to the ⑥ pin of the time base circuit through C4. The ⑥ pin is triggered. The ③ pin outputs a low level. The thyristor loses the trigger current and cuts off, and the light goes out. C3 and C4 in the circuit are coupling capacitors, which can prevent electrostatic phenomena caused by damage to individual components. C1, C1, VD, and VDW in the circuit form a 6V DC power supply. See the table on the left for component selection and production component list. Due to its small size, this circuit can be installed in a box. The circuit does not need to be debugged and can usually be successful in one go. No. Name Model Quantity R Resistor 500Ω 1 C1 Metallized paper capacitor 0.47u/400V 1 C2 Electrolytic capacitor 220u/16V 1 C3, C4 Metallized paper capacitor 0.01u/400V 2 C5 Polyester capacitor 0.01u 1 VD1 Rectifier diode IN4007 1 VD2 Zener diode 2CW57 (9V) 1 VS Triac 1A withstand voltage ≥400V 1 IC time base IC NE555, 5G1555, uA555 1 A, B homemade metal sheets 2