I am making a bi-polar 12V power supply with a centre tapped (12-0-12) AC transformer. On inspecting the voltages after the bridge rectifier (KBU-4B), the negative side produces -26V and the positive produces +10V.
Both sides have a 470uF cap before and after their voltage regulators (L7812-CV and L7912-CV) for smoothing and a 4.7k resitor at their outputs to simulate a load. Their outputs after regulating are +9V and -12V.
As both sides of the circuit are identical I would assume their outputs should also be identical. Is there something I am overlooking here?
The PCB below contains the + and - 12V outputs and a +5V output running off the +12V. I have disconnected the trace running to the 5V output whilst trouble shooting the asymmetry from the bridge rectifier. The output LEDs have also been replaced with 4.7k resistors