If we need to use 12V to 5V voltage regulator. This is the 5V 1500mA DC regulator circuit. Which is a simple circuit using IC-7805 to the fixed regulator 5 volts and TIP41-NPN power transistor to increase current up to 2A.
I use the 7805 power supply with the 12V battery. To reduce the constant voltage of 5 volts.
I try to use the load is 4.7 ohms 5W resistors. As principles, it will use the current about 5V/4.7ohms = 1A. I measure the current of about 0.7A and the voltage drop is 4.9V, but it is still usable. As Figure 1
Figure 1 Testing pure IC-7805 not over 1A current.
But sometimes we want a higher current. For example, I like to use a current of 1.5A. It requires a transistor to increase the output current up.
We’ve recommended this feature circuit is 12V to 5V 3A DC converter step down Regulator. But someone said the PNP transistor is not popular. They want to use an NPN type.
Today I recommended this simple circuit.
I use the TIP41 transistor. In principle, it can supply the current about 2A, which it is enough to use. I like this number. Because it is cheap, efficient, and reasonable.
As Figure 2 is the circuit diagram. Then, I test circuit with about the load, 2.4 ohms resistor. measure current approximately 1.3A, and voltage drop is 4.9V. It can be used as we want. As Figure 3
I put a Diode-1N4007 voltage to offset the loss of the transistor between pin BE.
We insert LED1 to indicated power on of this circuit and a series resistor-R1 is used to limits current to a safe value.
C1, C3 is filtered capacitors to smooth dc current input and output sequence.
C2, C4 is noise filter spark current.
While Q1 is working it will very hot so we must mount it with a large heatsink.
Component list of 12v to 5v voltage regulator
IC1___LM7805___5V dc regulator IC
Q1___ TIP41____2A 50V NPN power transistor
C1____1000uF 35V___Electrolytic Capacitor
C2____0.1uF 50V___Ceramic or mylar capacitors
D1____1N4007______1A 1000V Diode
LED1____LED any color as you like
R1____820 ohms 0.25W
Heatsink, wires and more etc.
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