IC1: LM317T, 3 terminal positive adjustable regulator Which you can add more voltage range with some resistor at the S3.ġ.5V, 3V, 4.5V, 5V, 6V, 9V LM317 Selector SupplyĬ2-filter capacitor eliminates the power spike voltage before comes to LM317.Ĭ6-capacitor filter DC voltage to smooth better, low noise. 0-30V 3A Variable Regulator using LM723.You can rotate S3 to select voltage out of 3V, 6V, 9V, and 12V. We often use the same does not change For example 9V, 12V to uses it instead of a battery. My first LM317 Variable Power Supply (1.2V to 30V at 1A) We can rotate the variable resistor-VR1 to change the output voltage, about 1.25V to 20V. When we switch the S2-selector to the fine mode. The circuit has two options you can choose. 5V to 1.5V DC to DC Converter circuit using LM317.0-30V 1A transistor Variable power supply.Second, the current of the diode bridge.If you need a high current of the output. Thus, the high power current will flow through the collector and emitter to the output, in the max current. The Q1 is running because it gets a current biased, There is a voltage across R3. When Q2 conducts, the high current will flow its collector and emitter to the base of Q1, the power transistor.
2n3055 transistor test driver#
The voltage across R1 causes a current biased to Q2, driver transistor. What can we do? To increase it up! We help it with the transistors.Īnd R1 limits current to IC1. But as we know LM317 can power out of 1.5A. Current boosting circuit for LM317Ībove I said the circuit can power the 3A output current. It will make the output voltage is very steady. The IC1 is the main, DC variable voltage regulator IC, the famous LM317. Then, the unregulated voltage comes to an input of IC1 through R1. And the R6 limits the current to save LED1 Next, the capacitor-C1 filters this becomes the pulsed DC. Then, the AC18V comes to a diode bridge-BD1, to rectifies ACV to DCV, pulsed DC. T1-the step-down transformer converts AC-main to the low ACV, 18V at 3A current.F1-0.5A fuse to protect the circuit when overcurrent.In the 3A adjustable voltage regulator circuit above.įirst of all, get an AC main to the circuit.