- on Test & Measurement
- Published in issue 7/2010 on page 66
(Summer Circuits 2010 article)
In some circumstances it may be necessary to select LEDs with closely matched characteristics. This design makes the job a whole lot easier. It uses two tracking current sources to allow the comparison of the two LEDs under test. LED current is adjustable by potentiometer P1 giving a range from 1 to 50 mA.