Dual channel stabilized power supply

Reliable power supply construction was taken from LINK.
Meter in this device measures voltage, intensity, checks the resistance and power of the system. It shows the current temperature, starts the fan when the temperature reaches 50 degrees Celsius and stops when it drops below 45 degrees Celsius. Its main element is Atmega8, this microprocessor was programmed using an adapter described here: **broken link removed**.



Transformer 200VA 2x24VAC and housing Z39 were used.
Changes of the original schema:

• rectifying bridges instead of rectifying diodes (3A diodes heat up too much)
• precise voltage regulation added (second potentiometer of 1kohm – voltage can be adjusted more precisely than via potentiometer of 10kohm)
• two power transistors on one display channel

Emitters of power transistors (R23 and R34 on the schema) are preceded by resistor 0,33ohm 5W.
Schema presenting connection of potentiometers and transistors:



Separate transformer from a desk lamp was used to power the meters. Boards were made in thermal transfer method, then digested in water solution B327.
The power supply reaches about 5A and gets temperature of about 65 degrees Celsius, when set at 1A (for short circuit) after 30 minutes.
Photos:




New front panel:




Link to original thread – ''Mocny'' Dwukanałowy Zasilacz Stabilizowany by Strzałi