On 6/3/2011 9:14 AM, DF3KV wrote:
> I never saw that happen with a constant voltage transformer (transducer).
> Are you sure yours is based on transformer/choke and not an inverter?
>
Constant voltage transformers (if we are talking about he same thing)
come in a wide variety of sizes. The maintain the "RMS" voltage at a
constant value +/- a small % and do so usually by distorting the AC wave
form. We used a number of them, all manufactured by SOLA, to provide
constant AC voltages into our calibration rooms. The waveform was
really ratty, but we were not concerned with wave form. Our power
supplies which wee conventional (with a lot of iron in them) didn't care
about the wave form. I calibrated voltage and current meters for
measuring down into the milivolt and miliamp ranges along with precision
resistors traceable back to NBS within 0.005%. Oscilloscopes, recording
instruments, bridges for measuring down into the milliohm range and
receivers to monitoring RFI signal strength.
It's been a long time, but that equipment seems rather primitive now.
73
Roger (K8RI)
> However, how do you measure AC with a moving coil meter?
>
> 73
> Peter, DJ7WW
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of John G3UUT
>
> Another caution, this time about constant voltage transformers. I had
> one of these and tried to use it to stabilise the mains to a signal
> generator to improve drift. It sort of worked but the main problem with
> it was that it distorted the mains waveform quite badly, sufficiently so
> that a normal moving coil meter read very inaccurately
>
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