I am making a + & - 12V power supply using L7812 and L7912. The former is a +12V regulator and the later is a -12V regulator. The Pos regulator is supplied with 25.2 VDC and the output is +12.1 V. However, the Neg regulator is supplied with -24.8 VDC and the output is -17.0 V.
At first I thought I had a bad L7912 so I replaced it and to my amazement, I still have -17 volts instead of -12 V.
I am aware that the pin functions are different on these devices.
Looking at the front, the L7812 pins are Input, Ground, Output
The L7912 pins are arranged as: Ground, Input, Output.
This has me baffled. Any ideas?
At first I thought I had a bad L7912 so I replaced it and to my amazement, I still have -17 volts instead of -12 V.
I am aware that the pin functions are different on these devices.
Looking at the front, the L7812 pins are Input, Ground, Output
The L7912 pins are arranged as: Ground, Input, Output.
This has me baffled. Any ideas?