I construct a very powerfull and reliable power supply for my laboratory that can give around 10 Ampere from 0-30 volt dc with 6 transistor tip3055 .
Lets see what we have here
in this pdf file you can find ,schema,pcb board,usefull information,all conections and part list
I made an aluminium rectangular box 310mmx200mmx180mm. There is not tte back side because i will place a huge heat sink
here you can see the pcb with 6 power transistor tip3055 (its the same with 2n3055 but in different case)
the main pcb and transistor pcb is ready for placement
transformer is and 2×12 volt 360 watt and yes it is made in GREECE!! You can also use 2×18 volts as described in the manual
If you already read the manual you will notice that you should done some tests using a lamp for making the required adjustments
Second step is 2 usefull meter ,one for measuring volts and the other for amper .You can find those in this section .We made two if those connecting in a differnet way so that measure the voltage and at the same time with the other one measure the amper.
Project is continued with a thermostat.It is a circuit with a thermistor stucked at the heat sink. There are 2 fan at the heat sink that is always working at a low voltage 5 volts.But when the heat sink rise more that 50 degrees Celsius ,the relay of the thermostat close and transistor works at full power 12 volt. One of this blows the air and the other one suck air .
R1 NTC 103 10 KOhm NTC Thermistor
R2 Resistor 4.7 KOhm 1/4 Watt 5% Carbon Film
R3 Resistor 100 KOhm 1/4 Watt 5% Carbon Film
R4 Resistor 5.6 KOhm 1/4 Watt 5% Carbon Film
R5 5 KOhms potentiometer
R6-7 Resistor 2.2 KOhm 1/4 Watt 5% Carbon Film
IC1 LM741 Operational Amplifier
Q1 2N2907 General pnp purpose amplifier and switching transistor
you can see thermistor attached to the heat sink
mow I place everything inside
those 3 resistors are shunt resistors
you can see heat sink here. It is a big piece of aluminium place 2 fans and electrolytic capacitors and the bridge
transistors are places inside the aluminium box. Those fans are off,but when thermostat reach 50 Celsius or more, both fan blow air inside.
Upper fans ,as told before works at 5v. When heat sink reach 50 celsious or more ,then works at 12 v