[Test-Equipment] Good scope for the job?

Sun, 10 Aug 2003 05:14:12 +0000

   You could use an existing 'scope by building a suitable voltage
divider with the appropriate cables and connectors, a low capacity probe
on a small circuit board, possible in a ventilated box.  You could
make one for each mains voltage so it always is presented as you wish,
such as 1.0 Volts peak or peak to peak.
   15 k Ohms at 25 Watts in series with a 37.5 Ohm 1/2 Watt resistor
should work out to be a 400:1 division, the 15,000. Ohm resistor goes
to the point being tested and the connection of the two go to the 'scope.
   Feed a high voltage (50 Hz.) square wave (20 Volts?) in, turn the gain
up and frequency compensate it like the low capacity probe if is isn't
good enough.  At 50/60 Hertz non inductive resistors are not necessary.

> I need a scope to study AC mains (UK voltage 240V) and possible 3 phase
> (440V) circuits. Any suggestions as to which scope? given voltage range,
> probe etc. If anyone is selling a scope that would suit this job please let
> me know or I will scan eBay. Must work in UK (240V 50Hz) but not looking to
> spend a fortune ;-)
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