How Haptic Actuators Work: ERM vs LRA vs Voice Coil vs Piezo

Ever felt a “click” from a touchscreen button that doesn’t physically exist? Or noticed your phone’s notifications each have a distinct feel? That’s haptics! And it comes down to four actuator technologies: ERM, LRA, voice coil (VCA), and piezoelectric.

In this video, we compare ERM vs LRA vs voice coil vs piezo haptic actuators from an engineering perspective — how each one converts electrical energy into motion, and the real tradeoffs between cost, precision, speed, size, and driver complexity:

Eccentric Rotating Mass (ERM) — cheap, simple, DC-driven, but slow to start/stop
Linear Resonant Actuator (LRA) — efficient and precise, but locked to one resonant frequency
Voice Coil Actuator (VCA) — wider frequency range and stronger output, at the cost of size and power
Piezoelectric — ultra-thin and fast response, but higher drive voltage and lower force

By the end, you’ll be able to explain how each actuator generates vibration and make an informed call on which haptic technology fits a given design — whether that’s a smartphone, wearable, automotive interface, or industrial control panel.

This lesson was created with the financial and technical support of our Friend of CircuitBread, @puiaudio , a manufacturer of haptic actuators and audio components.

More engineering tutorials, calculators, and resources at CircuitBread.com.

Chapters:
00:00 Introduction
00:26 What Is Haptics?
01:36 ERM (Eccentric Rotating Mass)
02:29 Linear Resonant Actuator (LRA)
03:12 Voice Coil Actuator (VCA)
04:02 Piezoelectric Actuators
04:55 Comparing the Four Technologies
06:27 Check out CircuitBread.com

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