Re: Identifying and Adapting Meters Followup on my own response

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: David Speck <Dave@xxxxxxxxxxxxxxxx>

Paul,

I checked the Tesla tuner schematic on the net, and indeed, the LEDs are 
indicating an AC voltage.  Just dropping in a DC meter in place of the LEDs 
will not work.
As I suggested, you could use a precision rectifier circuit as described 
below to detect a minimum voltage across a current sensing resistor in 
place of the two LEDs, for the most formal design.

A simpler alternative that MIGHT work would be to make a full wave diode 
bridge of germanium or Schottky diodes for minimum forward voltage drop 
(0.3 volts per diode for Ge or Schottky, vs. 0.6 per diode for Si), and use 
it to steer the current in the proper direction for your DC meter.
There might be a fairly wide null area though, in which the voltage would 
be too low to pass through the bridge, and the meter would show a zero 
reading.  However, this is also true for the dual LED arrangement, and that 
setup is known to work.  It's certainly worth a try.

Dave
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Having said that, and NOT having looked at the Tesla Tuner schematic in a 
while, IIRC, the tuner feeds AC to the LEDs, and relies on the human eye to 
integrate the pulses of light to balance the two LEDs' output.
If that is correct, a DC meter won't help you.  You will have to build a 
simple precision rectifier (otherwise known as an absolute value circuit) 
with an op amp, a pair of diodes and a few resistors.  Circuits for these 
are easily found with a Google search.
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> I would like to use one of these to indicate the output level of the Tesla 
> Coil Tuner, in addition to or in place of the LED. Any help will, of 
> course, be greatly appreciated. I will even accept well intentioned 
> criticism about what a stupid idea this is!! Regards.
> Paul