Vermes
Advanced Member level 4
The construction is based on universal LM317 with adjustable voltage from 1,2V to 37V and a current efficiency from 1,5A for LM317T.
It is a universal power supply with symmetric supply with a good current efficiency. Transistor BD244 with max Ic=6A along with LM317 was used in order to improve resistance of the metal elements to load. Additionally, it has big capacities at the input.
Characteristics:
- two independent single power supplies with adjustable voltage 1,2 (1,3)V → 25V (limit of the transformer) with a current efficiency up to 3A each, with 3,15A fuse (while description on the housing says that the fuse should be 2A)
- each module has a simple voltmeter on 7-segment displays and ICL7107
- basically it is 2x single power supply, but using a simple circuit (switch and relay), a symmetric connection is available. It is not symmetric from the beginning, because sometimes you need two independent adjustable voltages in a circuit
- to limit losses on active elements, divided windings was used and that is how the relay was made: to 12V and to 24V
And a short video showing the idea:
Link to original thread (useful attachment) – Zasilacz symetryczny regulowany do 2x25V i 2x3A (ogran. 2A)