ESR meter

ESR Meter

Easy to build electronic construction project for an ESR meter.

Written by Guy Fernando.


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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.


LCD animation


  • 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

Schematic diagram

Easy to construct

Wiring components to the main-board

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.

Programmed PIC16F1705
PIC16F1705 PIC Microcontroller.
Pre-Programmed Firmware for ESR Meter.
Version v1.00

Happy testing!