PW 1986 High Impedance MOSFET Voltmeter

[Yorkie]

I've e-mailed Joe the PDF Al.

The ranges are:

100mV
500mV
1V
10V
50V
100V
500V

You use either a DC probe which goes up to 500V, or an AC probe, which only goes up to 10V RMS (28V P-P) as it uses a BAT85 Schottky diode which won't stand any more than that. The advantage of the probe is that it doesn't simply measure 50Hz AC, it goes up to 150 MHz or thereabouts, and is primarily intended for measuring small RF voltages and peaking up tuned circuits. Obviously for higher 50Hz AC Voltages, a conventional multimeter will do the job perfectly OK.

You don't switch the meter from DC to AC, you just plug in the approriate probe. Details of constructintg the two probes is included in the article. Hopefully Joe will post the article shortly.

Hope that helps.