The attached file seems over complicated for a simple touch alarm.
It's got a rather unstable oscillator L1/C2 running in the 70MHz region. L1 is about 10 turns over a pencil diameter, but C2 looks an odd value,, but it sort of works.Touching T stops oscillation and is supposed to make TR2c go high.
This all seems a very odd way to do this. Does it work despite its design. But is there something very cunning I am not seeing?
Thanks,
Janet
It's got a rather unstable oscillator L1/C2 running in the 70MHz region. L1 is about 10 turns over a pencil diameter, but C2 looks an odd value,, but it sort of works.Touching T stops oscillation and is supposed to make TR2c go high.
This all seems a very odd way to do this. Does it work despite its design. But is there something very cunning I am not seeing?
Thanks,
Janet
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