This is the circuit diagram of 0-60V / 0-2A variable power supply. Of course this circuit used to cover the voltage range from 0 to 60V and current from 0 to 2A. The maximum current can be increased, if we add the power transistors needed. Note the power output, just to cite one example, if delivery 2A 12V source to have a voltage drop of 48V with 2A consumption giving us a dissipation of 100 watts, is not a heating source, so, care.
Close attention should be paid to the way in which the two transistors BC327 circuit current protection, which work in saturation cutting work, another deals only activate an LED indicator on-load when the voltage drop lights output and will have to press the RESET button provided for the case. This will activate the output voltage again.
As already mentioned, this source has an intensity control, which disconnects the output voltage. This does not mean that supports the intersection of the (positive and negative) output cables. We must avoid this situation if possible as this will cause the destruction of transistors and other circuit components, it should be noted that we are dealing with respectable power.
For example: 5V and 2A output, this represents 65V – 5V = 60V which must be dissipated by the output transistors 2A, are talking about the power loss of 120 watts as a small “electric fire” this heat, more heat produced by 10W consumption advantage, they must evacuate 130W between the radiator and a fan that helps to lower the temperature that produces this “heater”, otherwise, you can imagine the result.