This circuit can easily be assembled on a small piece of prototyping board. Use low-current types for the LEDs. They have a low forward voltage and are fairly bright at current levels as low as 1 mA.

My wish list for highly-integrated measurement instruments includes impedance or RLC meters. These instruments are especially interesting because they allow for so many different design alternatives ...

Digital multimeters (DMM), once called voltmeters, have been described as the tape measure for engineers in the new millennium. With electronics and electrical circuits included in almost every ...