Autoranging Capacitance Meter

Most commercial digital Capacitance meters can measure capacitors from a few pFs (picofarads) up to 2,000 µF (microfarads). A few are able to measure up to 20 mF. Circuits like audio power amplifiers, switchedmode power supplies, printers and photocopiers often incorporate really large capacitors in the hundreds of mF range (1 mF = 1,000 µF). With this cheap circuit, you’ll be able to measure any capacitors of almost any ‘size’, from picos to Farads.Main Features– Low cost, direct reading,– Wide range, (from a few pFs up to several Farads)– Auto-ranging, (no range switches)– Auto-zeroing, (nulls stray capacitance of connected test leads or test jig on power up)– Low-Battery indication– Simple setup

The parts list and the circuit diagram indicate different transistors in position T1. Both the BC559B and the BC557B will work in this circuit, although the BC559B is the preferred device. The Farnell order code for the Pactec case used in this project should be: 736-442.