This 300V variable power supply circuit diagram is designed with high voltage transistors. This 300V variable power supply circuit diagram can provide an output voltage between 10 and 300 volts which can be adjusted with the potentiometer P1.
Transformers typically used in such sources have several windings of high voltage and low voltage winding. In this case we used a winding high voltage 300 V, while a winding 9 V supply was used for circuit stabilization. This circuit is very simple and need not explain.
An 50v bench power supply can be made using electronic diagram below which is designed using LM10 op amp and 2n3055 transistors. This LM10 2n3055 50v bench power supply allows an output voltage regulation in a range between 0 and 50 volts and the output current can be limited to a maximum of 2 A.
Output voltage increases linearly with the amount of resistance potentiometer P1, while the current can be adjusted linear using potentiometer P3. Potentiometer P2 serves to regulate maximum output current (maximum value is 2 A).
If you wish to use a double symmetrical power supply circuit but don’t have a center trapped transformer you can use an electronic circuit in the following configuration. This double symmetrical power supply circuit uses a second rectifier bridge coupled with secondary coil of the transformer using two capacitors (C1 and C2). Because the DC voltage produced is not in galvanic contact with the terminals of the transformer, where is connected the other one bridge rectifier, both voltages can be combined into a symmetric voltage.