Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

Programmable Current Source by LM317

Programmable Current Source by LM317

Accurate and stable current supplies are generally needed in electronic labs especially for creating V I curves, charging and discharging batteries, preloading power supplies and for many other purposes and applications.
This circuit provides a current supply that can be programmed by using three digit BCD switches that allows us to set the current from 1 mA to 999 mA. It is really a low cost easy to build and easy to use device. The components are a three terminal adjustable voltage regulator – LM317 , three BCD switches (shown in the figure 1) and a handful metal film (1% tolerance) resistors.

The circuit operation is very easy. First connect a DC power supply’s (3V to 40V) positive terminal to the “IN” and ground terminal to the “ADJ” pin of the LM317. For instance when you set the MSD (Most-Significant-Digit) to two and the other ones to zero, the BCD switch connects the 6.2 Ohm resistor from the LM317’s output to adjust pin. The LM317 forces 1.25 V across the 6.2 Ohm resistor, causing 200 mA to flow from the output pin through the resistor, and to the ground of the power supply.

Visit Here for more.

 

More Articles to Read

LED traffic light
LED traffic light
Estimating Power for ADSP-BF561 Blackfin® Processors
Estimating Power for ADSP-BF561 Blackfin® Processors
Teach Your Arduino to Switch Itself Off!
Teach Your Arduino to Switch Itself Off!
Control a tracked robot with your mind (or joystick)
Control a tracked robot with your mind (or joystick)
A 400W (1kW Peak) 100A electronic load using linear MOSFETs
A 400W (1kW Peak) 100A electronic load using linear MOSFETs
Shirt Pocket Transceiver with the Si5351 and OLED
Shirt Pocket Transceiver with the Si5351 and OLED
All metal C930e webcam
All metal C930e webcam
The Soldering Tools That Make Your Life Easier
The Soldering Tools That Make Your Life Easier
App note: Operation evaluation of ultra low ON resistance MOSFET supporting quick charge for 1 c ...
App note: Operation evaluation of ultra low ON resistance MOSFET supporting quick charge for 1 cell Lithium ion battery protection
Synthesized Sidetone
Synthesized Sidetone

Top




Shares