Handy capacitance tester on Arduino

If you are working on capacitance sensitive projects, it is recommended to check capacitor value before use. Practically any multimeter already have capacitance measure mode. If you are not satisfied with its range or want to have dedicated device, consider of building one. Braulio777 have written pretty illustrative instructable where he shares all building steps on how he built cap meter. It is capable of measuring capacitance from 0.000pF 0.001pF to 1000uF. The meter is built around Arduino where external components are assembled on separate Arduino proto shield with 16×2 LCD on top. He run several tests that prove that meter works within specs. With enclosure and battery it becomes decent portable meter. Continue reading

Measuring low capacitance

Probably any standard multimeter have a capacitance measurement function. But they are limited in measuring small capacitance. Measuring below 200pF gives unreliable results. Also resolution varies around 1pF. If you’re radio amateur capacitance like 2.7pF is a common value that needs to be measured or checked. One way is to purchase precise LC meter or simply build a low cap meter from parts around you. Following design is based on Attiny2313 microcontroller which measures capacitance from 1pF up to 2500pF with 0.1pF resolution. Results are displayed on standard LCD. Unit can be calibrated with 1000pF 1% capacitor. It is available as kit or take a chance to build it as all necessary info and software is available for download. Continue reading