On Sun, Jun 28, 2020 at 09:44 AM, mosaicmerc wrote:
nteresting...I did use my (3 year old) Variac last year to develop? a thermal
sensor/display circuit for 3 phase bus-bars in electrical panel/switchgear.
The circuit had to be low current, compact and? have good heat tolerance
being in an enclosed panel. So I designed a transformer less, capacitive
coupled? power supply that was viable from 110VAC thru 330VAC . My Variac?
is a 0-130VAC unit, so I also used a 1:3 transformer? salvaged from some old
gear to step up the test voltages.
Interesting... I did use my variac to implement an inexpensive variable HV DC supply, with three diodes and three capacitors forming a rectifier / tripler, able to go from zero to over 500 VDC.
I used this to regenerate the electrolytic caps in my old 547 scope, after disconnecting them from their circuits.
This arrangement can also make a wife a widow if not used carefully, but so is everything inside a 500 series oscilloscope.
Ernesto
