Re: Tesla Coil Patent USP # 577670

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <teslalist-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

 > It is the LT1088 (Digikey ~ $20).  It is officially known as a wideband
 > RMS-DC converter.  It can easily be set up as a very precise power meter.
 > 1% accuracy DC - 50 Mhz and 2% accuracy to 100 Mhz.  300 Mhz BW.  Basically
 > it converts input waveforms into heat which drives a diode junction in the
 > IC.  It is a very precise thermo-electric device which is electrically
 > isolated from the DUT.  Go to Linear Technology web site and down load
 > specs and applications and you'll see what I mean.
 >
 > You can easily follow power around your TC or O/U device and get real quick
 > accurate information about what the circuit is doing.  A good place to
 > start is to measure the power going into and out of a battery or PS in real
 > time.  The results are sure to disappoint 99.999% of all O/U'ers when
 > testing their hoped for O/U device.
 >
 > Caveats:  If you build this simple little device be sure to build the
 > crowbar circuit to prevent diode damage.  Also, For higher powers measured,
 > a shunt or potentiometer should be used.  Also, build it with a battery PS
 > so it can be "floated" around your circuit.
 >
 > RWW

	This is a most interesting device, and I hadn't heard of it before.
Its operation is similar to that of a wattmeter using dual-filament
tubes in which the power to be measured is applied to one filament and
the power input to the other is varied to give equal brilliance.  If the
latter is DC measurement of the power is simple.  I've built a number of
such gadgets which used CdS PEC's to sense the brightness of each
filament and then used a feedback circuit to apply power to the
reference filament.  Note, however, that the LT1088 is a device for
measuring RMS current, NOT power.  I can't see any way it could be
employed in construction of a watt meter, but maybe I'm missing
something.

Ed