- on Test & Measurement
- Published in issue 7/2003 on page 0
Low-cost Inductance Meter
This inductance meter consists, all in all, of four components that can be mounted on a small piece of prototype board in a jiffy. In order to use this meter the following are also necessary: a power supply, a pulse generator and an oscilloscope. So this is not really a complete measuring instrument, but more of a handy tool for the hobby laboratory.InductorsAn inductor does with current what a capacitor does with voltage, namely: store and release. A constant voltage across an ideal inductor causes a linearly increasing current. Or mathematically: dI/dt = U/L.
The formula to determine the coil inductance should read: L = 1.2 dU/dt, not L = 120 dU/dt. The error in the calculation starts at: dIL/dt = 0.1 dU/dt; this should be dIL/dt = dU/dt) / 0.1.