T i m wrote:
Hi All,

snip
I just did some comparisons between old and new probe using my DMM and
the gas stove and noted the following with either (probe, not DMM) in
the gas flame (simulating pilot).

New device .. open cct voltage 30mV, short cct current (DMM on 2mA)
250uA.

Old device .. 23mV and 200uA ?

So, from that very crude test the old thermocouple isn't 'dead' but
maybe down on performance (especially when not in a 'strong' flame ie
only a 'pilot' not a low gas ring) enough to make a difference?

I'll see what happens when I ahem, sorry, 'the Corgi bloke', put's
it back later... "You know anything about parachutes ...?" ;-)

The current isn't real.
The meter is applying a resistor across the leads so that at its nominal
200mv fullscale, it'll read full current, so 2mA range has a 100 ohm
resistor across it.

As the thermocouple has a resistance way under 100 ohms, it's just reading
out the voltage.

The voltage ranges can be handy for reading out very low currents (nA)
similarly.