Hello
I made a touch switch in a PCB based in the following schematic
When touching the plate with a finger the BJT turns on and the 555 trigger pin goes LOW activating the pin 3 (OUTPUT).
The time the circuit is on depends of the 100K resistor and the 10u capacitor
The circuit works pretty well with a power supply with 9V.
When I use a 9V battery the circuit works well if I’m not isolated from the earth (touching the floor with a bare foot)
If I’m isolated from the earth (using shoes) the circuit stops working after 3 or 4 tries and only works again if I touch the earth.
If i use an oscilloscope to probe the trigger pin of the 555 the circuit works with no issues.
How can I improve the circuit to work to prevent this behavior?
Thanks
I made a touch switch in a PCB based in the following schematic
When touching the plate with a finger the BJT turns on and the 555 trigger pin goes LOW activating the pin 3 (OUTPUT).
The time the circuit is on depends of the 100K resistor and the 10u capacitor
The circuit works pretty well with a power supply with 9V.
When I use a 9V battery the circuit works well if I’m not isolated from the earth (touching the floor with a bare foot)
If I’m isolated from the earth (using shoes) the circuit stops working after 3 or 4 tries and only works again if I touch the earth.
If i use an oscilloscope to probe the trigger pin of the 555 the circuit works with no issues.
How can I improve the circuit to work to prevent this behavior?
Thanks
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