Circuit Diagram Knowledge

A very simple DC motor speed controller circuit can be constructed using a LM317 voltage regulator integrated circuit . This DC motor speed controller can be used for speed control of mini drills or for other small DC motors . This motor controller circuit will provide a large output current . The maximum output current from the secondary turns of the transformer shout provide 1.5 times of the maximum DC output current . The output voltage and the speed ( rpm ) is set by the P2 variable resistor .

As soon as the current drawn exceeds a certain value , T2 will be switched on . This results in a base current for T3 so that R5 is in parallel with R6 . This automatically raise the output voltage to counter a threatened drop in rpm . The moment at which this action occurs is set by P1 .

Another power supply electronic circuit that is designed using LM317 voltage regulator can be designed using few electronic parts . This power supply circuit is a very simple low cost switching regulator electronic project that is based on the LM317 three terminal regulator .
As you can see in the circuit diagram this power supply electronic project require few external components and a LM317HV regulator . The input voltage required by this electronic project must be between 8 and 35 volt , and will provide a variable output voltage over a wide range , from 1.8 volts up to 32 volts
The maximum output current that can be delivered by this LM317HV switching power supply electronic project is up to 3 amperes .
C1 , C4 capacitors must be a solid tantalum type and L1 coil must have a 600uH inductance . For L1 coil you can use a Arnold A-254168-2 core with 60 turns .