Capacitor ESR Meter
Electrical
Intermediate
ESP32
Arduino C++
About this project
EsrBolt is an ESP32-based equivalent series resistance (ESR) analyser for electrolytic capacitors. Using a charge-pulse injection technique, it drives a known current pulse through a precision 33 Ω sense resistor into the capacitor under test, then samples the ESP32's 12-bit ADC within 80 µs of pulse onset — before appreciable capacitor charging — to capture the initial resistive voltage drop. ESR is computed from Ohm's law: ESR = V_probe × R_sense / (V_supply − V_probe). A TM1637 4-digit display shows the result in milliohms; tri-colour LEDs and a buzzer provide instant quality classification; and a soft-AP web dashboard logs up to 20 readings with per-bar colour-coded history charts.
What you get
- Complete, commented source code
- Full components list with quantities
- Pin-by-pin wiring guide and connection table
- Step-by-step upload and testing guide
- Project report (.docx, IEEE style)
- Presentation slides (.pptx)
