547 front panel 100V source


snapdiode
 

I am feeling lazy and I am wondering how much current the 547 calibrator can deliver in its 100VDC position. I want to power a Magic Eye, it needs 1mA.


Peter H
 

Looks like R960 is 50k.


snapdiode
 

It's shorted out when the switch is in 100VDC mode. Actually I never knew the 100VDC position forces 5mA DC through the front panel current loop! A new discovery for me. In any case, in the 100VDC position, the negative power supply to the multivibrator is cut, so half a 12AU7 is powering the calibrator through 225V through 250 ohms. I think I'm OK.


Harvey White
 

Oddly enough, they do the same (set to 100 volts output) arrangement for the PG506.

Harvey

On 12/19/2020 6:49 PM, snapdiode via groups.io wrote:
It's shorted out when the switch is in 100VDC mode. Actually I never knew the 100VDC position forces 5mA DC through the front panel current loop!
A new discovery for me.
In any case, in the 100VDC position, the negative power supply to the multivibrator is cut, so half a 12AU7 is powering the calibrator through 225V through 250 ohms. I think I'm OK.