TheRadioBoard

Hi All, I thought I would show my bench power supply. It started off as an HP VTVM but it mocked my attempts at calibrating it so I rewired the power supply section to the existing banana jacks. One set of jacks has the 6.3VAC winding wired to it and the other set has the regulated 245VDC. Since it already had a nice meter installed I measured the current required to deflect the meter to the “3” position and used ohms law to add in enough resistance to make it read 300V. There is a 39K 25W bleeder resister across the output so the meter won’t peg when it’s unloaded. I use an external Weston 100ma current meter to monitor the load. It puts out 80ma B+ and 2A of 6.3vac before it goes out of regulation spec. Not much work to get a regulated bench A & B power supply with meters. I got an old project off the not working shelf too!


Doug