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 an unusual oscillator, but it needs to oscillate reliably yet be easy to stop when you touch it. You say it does this, so it does work.
The oscillator frequency is not important so instability doesn't matter.