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Guy Fernando (M0OOX) presents in this article, instructions to build an ESR (Equivalent Series Resistance) meter for testing the health of
electrolytic capacitors. The instrument displays capacitance and ESR on a digital LCD readout, with an optional audible tone indicating the
condition of the capacitor under test. At the heart of the meter is a 14-pin PIC microcontroller, using just a handful of other cheap
components a feature rich ESR meter is easily constructed.
- Digital LCD readout
- ESR range 0.01Ω to 50Ω
- Testing frequency 100kHz or 50kHz
- Low test voltage for in-circuit testing
- Audible test result tones
- Auto power down
- Automatic testing of capacitor
- Probe resistance compensation
- Battery supply voltage compensation
- Capacitor stored charge protection
- Low and high battery warning
- Open / short circuit probe detection
Simple circuit diagram
Easy to construct
Buy the pre-programmed PIC microcontroller.
At the heart of the ESR meter design is a PIC16F1705 PIC microcontroller. If you would like to try building this project yourself, the
PIC may be purchased below fully pre-programmed and ready for use. The price includes postage and packing via Royal Mail Signed For service,
either to mainland UK or world-wide.