Design of a Microcontroller-Based Digital LCR Meter for Electronics Laboratories in Nigerian Polytechnics

Background: Inductance, capacitance, and resistance measurement instruments are essential tools in electronics laboratories but remain expensive imports for most Nigerian polytechnics. A locally constructed digital LCR meter can reduce dependency on costly imported equipment. Aim: This project designed and constructed a microcontroller-based digital LCR meter for use in electronics laboratory teaching at Nigerian polytechnics, with testing at Moshood Abiola Polytechnic, Ogun State. Methods: An STM32 ARM Cortex microcontroller was used to implement an impedance measurement algorithm based on AC bridge techniques across frequencies of 100 Hz, 1 kHz, and 10 kHz. A 3.5-inch TFT LCD provided measurement display. Calibration was performed using precision standard components traceable to NIST standards. Results: The instrument measured resistance within 1.2%, capacitance within 2.8%, and inductance within 3.5% of reference values across their respective useful ranges. Component cost was NGN 18,000. Conclusion: The constructed digital LCR meter meets practical accuracy requirements for polytechnic laboratory instruction and substantially reduces equipment procurement costs. Institutions are encouraged to incorporate student-built instruments in laboratory curricula to simultaneously build practical skills. Keywords: LCR meter, microcontroller, electronics laboratory, polytechnic, Nigeria.