RE: strange vttc

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

Original poster: Jim Lux <jimlux-at-earthlink-dot-net> 

At 07:55 AM 3/31/2004 -0700, you wrote:
>Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
>Instead of a HV probe, couldn't one just wire several resistors in
>series, read the drop across one of them and just apply Ohm's/
>Kirchhoff's law? Maybe those 10M resistors used for draining the primary
>caps? Three resistors will give 1/3 of the applied voltage across any
>single resistor; 4 resistors-1/4.  If you think the 4000V label might be
>correct, go with 5 resistors, a 1000V meter could do that one.  I don't
>know why I haven't done this myself, I have been putting 120VAC into the
>HV windings and measuring the output of the low voltage side, and figure
>my ratios.  I'm not sure how accurate this is, but it seems to be pretty
>close.
>
>Randy

Watch the power dissipation on the resistors when you do this.  4kV across 
40 Megohms is almost half a watt (0.1 watt per resistor), which should be 
ok, but if you start measuring your NST output you'll find you're burning 
up resistors.


Applying 110V to the HV winding and measuring the LV winding is the usual 
way to do it, just because it's safer.  However, it doesn't give you a feel 
for what the "loaded" output is, and for inexpensive transformers, there 
might be a fair amount of voltage drop under load.