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5V switching regulator circuit using transistor BC337

This is 5V switching regulator circuit using transistor, decreases the size voltage or Step down voltage converter circuit. Make voltage output there is the size voltage a little more input at from circuit picture will decrease volt 6-18V from be left 5V. It give current get 100mA. in working in switching forms The strategy works as follows.

Step down voltage converter 5V using transistor BC337

The old circuit

The new circuit diagram

As soon as we enter the voltage to the transistor circuit Q1 and Q2 are connected as the astable multivibrator, the circuit will generate the frequency output at collector of Q2 before send to base pin of Q3. Q3, which will act like the on-off switch, Q4 works by applying voltage to determine the collector pin, But must pass before R6 base of Q4.

When base pin of Q4 has low voltage will cause Q4 begin working , C3 will charge through coil- L1. The ouput voltage will increase up continuously, but when have voltage more than 5 volts will results to Q5 working since have a voltage bias at pin base in way of ZD1. The transistor Q1 is stopped, the pin base is equivalent to ground there. The circuit shutdown frequency out, Q4 will stop working.

Because the voltage at the base pin of Q4 through R5 output so not have voltage., Q5 so stop working . Then Q1 is working again. And The behavior, it would go like the first one. Cause the loop to do this. However, there are very high, thus making has output 5 volts to appear at it.

The components layout (non PCB)

Components list
Resistors size ¼W +5%
R1, R4, R7_____4.7K
R2, R3________47K
R6___________100 ohms
C1___________0.0015uF 50V polyester
C2___________0.01uF 50V___polyester
C3___________170uF 16V___electrolytic
Q1, Q2, Q3, Q5___BC548___ 45V 100mA NPN Transistor
Q4_____________BC337__45V 800mA PNP Transistor
D1_____________1N4001__1A 50V Diode
ZD1____________5.1V 500mW___Zener diode
Other components
L1-transformer toroidal core diameter 2.5-3.0 cm.
Copper wire size 0.4 mm.

This Post Has One Comment

  1. Regarding your coil, how long is the copper wire or how many turn on the coil as you didint mention. Tq hear you soon

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