## Friday, May 8, 2015

### Circuit Schematic Regulated DC Power Supply using Transistors

Eltronicschool. - Do you need circuit schematic for regulated DC power supply based on transistors? We think circuit schematic like in figure 1 below can be used as you reference to build Circuit Schematic Regulated DC Power Supply using Transistors.

This circuit is a low ripple regulated DC power supply that designed base on transistor. Transistor voltage regulators are suitable for this application where high output current is required in this condition. Conventional integrated series regulators can be used like LM7805 can only deliver up to 1A. Additional series pass transistors have to be added to the 7805 based regulator circuit for improving their current capacity.

In this article beside we will show you circuit schematic of Regulated DC Power Supply using Transistors, in here we also describe this circuit and give you special software to create or drawing this circuit in the last.

Circuit Schematic Figure 1. Regulated DC Power Supply / Circuitstoday

Component List
1. D1 = 5A Bridge diode
2. C1 = 1000uF/ 50V
3. R1 = 2K2
4. C2 = 100uF/50V
5. D2 = Zener Diodes 500mA
6. Q1 = 2N3054
7. Q2 = 2N3055
8. R2 = 56 ohm
9. C3 = 470uF/50V
10. R3 = 10K
Description

Circuit schematic like in figure 1 above is Circuit Schematic Regulated DC Power Supply using Transistors. From this circuit schematic using two transistors Q1 2N3054 and Q2 2N3055. According Circuitstoday describe this circuit that the circuit shown below is a basic series voltage regulator based on transistors. Transistor Q1 (2N 3054) and Q2 (2N 3055) form a darlington pair. Resistor R1 provides the base current for Q1 and also keeps the zener diode D2 in the active region. The overall working of the circuit can be demonstrated by explaining two situations.
1. When the input voltage (output of the rectifier section) increases, the output voltage of the regulator (Vout) also increases. This increase in Vout decreases the base emitter voltage of Q2 because the zener diode D2 is operating in the breakdown region and the voltage across it is unchangeable. This decrease in VBE increases the collector emitter resistance  of Q2 and so the output voltage (Vout) gets reduced accordingly.
2. When the output load increases, the output voltage (Vout) gets reduced. This decrease of output voltage (Vout) makes VBE of Q2 to decrease. This reduces the collector emitter resistance of Q2 and so the output voltage gets increased accordingly.