Recent content by NoTomorrow

Hi Willy, When I was testing and experimenting with it, I found that the component values are not that critical. The 560 ohm resistor should be selected to suit the battery voltage which could be from 3 to 12 volts. For a 6 volt battery, 220 ohms will be sufficient. For a 9 volt battery, 390...

Yes Willy, I realize that there are EM fields all around me, but the LED only illuminates when the probe is connected to a large metal non-earthed object or of course to an earthed metal object. As I replied to Jony, if it were capacitance effects, I'd expect it to flicker almost randomly.

Thanks Jony, If it's just stray capacitance, wouldn't I be getting spurious results? Like the LED flashing when I touch the probe tip etc.? I get a steady LED on whilst it's connected to ground, but the LED goes on for a few seconds the extinguishes when I touch the probe to any large...

Thank you Jony130, Yes, the circuit is powered just by the battery - no connection to Earth.

Hi guys and gals, Here's a simple circuit mostly just an LED circuit with a Darlington pair. My question relates to the base current to the probe. If the probe is connected to an unearthed metal toaster (not plugged in), the LED glows briefly then goes out. If the probe is connected to the...