Adjustable electronic DIY circuit with LM317 IC
Every electronics experimenter or technician needs a voltage adjustable power supply to power different kinds of circuits. For example, you will need 1.5v to test LEDs and 5V to test a 5V circuit, so here is the one you need.
This extremely simple circuit is useful to adjust voltage between +1.5V To +37V.
Using a well known voltage regulator IC LM317 from national semiconductor.
The LM317 can handle 1.5A(1500mA)MAX current. Cin and Co are electrolytic capacitors and Must be selected according to the value of voltages.
For example, if you want input only +12V, then you should use least 16V 1000Uf for Cin and same for Cout, (25v,1000uf is safe in 12v circuit) But you must use higher value capacitors when input more voltage or you will fry the capacitors!
R1 and R2 is used to adjust ouput voltage, so you must choose R2 value that is appropriate to output.
You can replace R2 with a 10k variable resistor to adjust the voltage anytime rather than fixing it with a fixed value resistor. And don’t forget to attach a good heat sink on the LM317 to reduce the heat.