Re: New Vector Monitor Project: Deflection I & V Measurments

A speaker is not all that inductive compared with a yoke. The current readings
are quite a bit less than I was thinking. Maybe I'm just a bit too "worst case"
for my own good.

Then again, I was thinking more G08 than Wells. And my "worst case" scenarios
were taking game board lockups into account.

James Nelson wrote:

> Ok, I just measured I & V on Tempest: Here is the data:
>
> Procedure:
>
> 10X scope probe used, X&Y measurements are at output with respect to ground,
> so they are off by about 2 volts due to Voltage drop across the shunt
> resistors. Current measurements taken by measuring voltage across 1.5 Ohm
> shunt resistors with scope. 2 Volts typ peak across 1.5 Ohms, 4Volts Max.
>
> Data:
>
> Voltages X&Y approximately +/- 25V peaks
> Current: typical peaks about +/- 1.3 Amps
> Current: Max peaks about +/- 2.6 Amps
>
> Conclusions:
>
> Without a precise RMS measurement, I'm going to estimate a typical RMS Power
> output of
> about 25 Watts.
> Peak Instantaneous Power output was 65 Watts.
>
> The LM3886 can do 68 watts continuous into a 4 Ohm load and 135 watts peak.
> To compare these numbers directly, one would need to know the impedance of
> the yoke at the frequencies used (approx. audio up to 100 kHz) So far, it
> still looks like it might be a good match to me, and worth testing out.
>
> Comments Graciously Requested
>
> James
Received on Fri Nov 5 13:49:54 1999