Touch Switch

Posted on Oct 27, 2012

The MPF102 (Q1) can be replaced with a NTE451 or ECG451, but still widely available. JFET-N-CHAN, UHF/VHF AMP. The 2N3565 (Q1/Q2) can be replace with a 2N2222(A), BC107, BC108, BC109(A/B/C), NTE123A, or ECG123A. The TIP31 (Q3) can be replaced with a NTE196 or ECG196, but is a common type and widely available. The 'Touch Plate' can be anything non corrosive. I use a silver quarter. You can also use a small relay instead of the #53 bulb.

Touch Switch
Click here to download the full size of the above Circuit.

R1 22Meg resistor R2 47K resistor R3,R4 100K resistor R5,R6,R7 2K2 resistor C1 Capacitor, 22?F, 25V C2 Capacitor, 22?F, 25V Q1 MPF102 Q2,Q3 2N3565 Q4 TIP31 La1 Bulb, #53

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