PSU-8 3-Rail Adjustable PSU
A 3-rail (2 x positive and 1 x negative) adjustable linear regulated power supply. This PSU was developed for applications which require two rails for audio circuits (+/- 15V, +30V/-10V etc) and a separate supply for noisy circuits such as LED indicators, relays, logic modules etc.
The module uses the LM317 for the positive rails and the LM337 for the negative rails and is designed so that the regulators can be attached to a bracket or to a chassis (insulating washers must be used).Single or multi-turn trimmers can be fitted for rail adjustment. LEDs are fitted to indicate the presence of power on each rail and to provide a minimum load to the regulators. The table shows a couple of configurations commonly used. One is the symmetric dual rail for op-amp circuits and the other is the supply required for the 1176 module. The aux supply rail is adjustable from 4.2 to 9.5V with the values shown. In order to achieve these outputs, it is required that a suitable transformer be used to provide sufficient DC voltage to the inputs of the regulators.
The module uses the LM317 for the positive rails and the LM337 for the negative rails and is designed so that the regulators can be attached to a bracket or to a chassis (insulating washers must be used).Single or multi-turn trimmers can be fitted for rail adjustment. LEDs are fitted to indicate the presence of power on each rail and to provide a minimum load to the regulators. The table shows a couple of configurations commonly used. One is the symmetric dual rail for op-amp circuits and the other is the supply required for the 1176 module. The aux supply rail is adjustable from 4.2 to 9.5V with the values shown. In order to achieve these outputs, it is required that a suitable transformer be used to provide sufficient DC voltage to the inputs of the regulators.
Aux Rail (LM317)
V+ Rail (LM317)
V- Rail (LM337)
R6
Vout
R8
Vout
R7
Vout
560
4.2 to 9.5V
2K
11.9 to 17.2V
2K
-11.9 to -17.2V
560
4.2 to 9.5V
4K7
26.1 to 31.5V
1K
-6.6 to -11.9V