Hello,
I'm building this circuit to create +/- 9 supply using a 12VAC wall-wart.
https://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf
My VDC measurements [with a load] at the output of the regulators are both fine, however, when I flip my multimeter to measure VAC it reads between 17 to 18vac between the positive regulator output and ground, and 0VAC between the negative regulator output and ground.
Additional measurements are:
37.9VAC and 17.5VDC on the cathode of D1
0VAC and 17.5VDC on the anode of D2
I've tried adding larger additional filter caps, as well as diodes across the in/out of the regulators, none of which has had any effect.
I've rebuilt this several times on a breadboard, always with the same effect, so I don't believe I'm omitting anything or misreading the schematic.
It powers the circuit I intended to use it with, but leaves a very noticeable AC hum/oscillation on the output.
Any ideas on what I'm missing?
Thanks in advance!
I'm building this circuit to create +/- 9 supply using a 12VAC wall-wart.
https://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf
My VDC measurements [with a load] at the output of the regulators are both fine, however, when I flip my multimeter to measure VAC it reads between 17 to 18vac between the positive regulator output and ground, and 0VAC between the negative regulator output and ground.
Additional measurements are:
37.9VAC and 17.5VDC on the cathode of D1
0VAC and 17.5VDC on the anode of D2
I've tried adding larger additional filter caps, as well as diodes across the in/out of the regulators, none of which has had any effect.
I've rebuilt this several times on a breadboard, always with the same effect, so I don't believe I'm omitting anything or misreading the schematic.
It powers the circuit I intended to use it with, but leaves a very noticeable AC hum/oscillation on the output.
Any ideas on what I'm missing?
Thanks in advance!