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100 March 2006
I am plagued with trying to determine when my oil burner ignition
transformers have died. These step-up
transformers generate 9,300 VAC at
about 25 mA (new style electronic
types aren't a problem: they die dead).
In the old days, I used to test them by
shorting a screwdriver across the secondary to see if the sparks came from
the screwdriver blade or from broken
down insulation on the secondary
winding (been knocked off my bucket a
few times, but not dead yet!) Then they
drop to 6-7 kVAC output, and will not
reliably ignite the oil burner (though
will still ohm out correctly). Does
anyone have a good circuit (read:
simple and cheap) that can load these
and give me a go/no go reading on
keep hearing about a snubber circuit
for inductive loads. Do I really need to
use a snubber circuit for just a relay?
If so, what would be the simplest
In the meantime I will continue to
use my interface as it works fine.
#3062 Paul Webley
I need cross references to
standard part numbers for these
RadioShack transistors. RadioShack's
website was a lost cause.
NPN, RS2010, Silicon, High Gain,
PNP, RS2034, Silicon, General
NPN, RS2042, Silicon, Power,
#3063 James Tadlock
I am currently interfacing my PIC
project to several mains relays using
an opto-isolated triac (with zero crossing). The current draw required by the
mains relay is only 11 mA and the
opto-isolated triac is rated at 100 mA.
I am currently using the interface and
it works perfectly with no heat from
My question is: Do I need to use
zero crossing for relay control? And, I
[#1061 - January 2006]
I have six six-volt batteries wired in
series to achieve 36 volts. I have
tapped the neg to the pos across two
batteries and got 12 volts.
Can I wire all three (sets of two) and
get 12 volts with lots of amps and run a
large inverter? That would be running
series and parallel in one operation. I
would have to be using both sources at