I was trying to repair my tek 2236 and was in need of measuring a -2kV line, only problem: my best Multimeter can only do 1000 V so I had to yank up 30 3k3 Ohm resistors in series to make a 100M Ohm Resistor. All put into some trash plastic tube makes a usable series resistor for the MM.
Be sure to watch the safety advice and keep your hands off the circuit under test!
So I put the old insulation transformers case to retirement and put it into this new space-saving case to fit my bench perfectly besides the old Heathkit VTVM. I can just repeat my warning: THIS IS NOT legally an insulation transformer! I do NOT use it to be able to touch its output, I only use it as a current limiter on newly built circuits. So enough for the legal crap, enjoy the video:
Finally it seems I made something actually useful 😀 This board is to control my fathers vinegar machine.
I provides him with an easy to use interface to set a sequence of up to 4 motors to control vinegar and air pumps. But be warned, this is a prototype – not the final design. For now the buttons’ response is hell and save/load/reset functions are not implemented. It is based on an atmega168 from avr but I think the final version could go down to an atmega88 (~5k flash in use now). Enjoy the video:
Here is my first draft >>>WARNING this is NOT the board, just my first idea!!!<<< the concepts are there, all pinouts can be derived from the software. There will be a nice schematic in v1.0!
The software: seqmot0.1