Dimmer module for 16/24A 600V High Load, 1 Channel, 3.3V/5V logic

Discontinued RobotDyn SKU: RD-AC-DIM-1CH-HL
Dimmer module for 16/24A 600V High Load, 1 Channel, 3.3V/5V logic

Overview

The RobotDyn 16/24A High Load Dimmer is the industrial-grade sibling of the standard 1-channel AC dimmer. It uses a larger TRIAC (BTA16 or BTA24) capable of switching loads up to 600 V AC at 16 A continuous (or 24 A peak with proper heatsinking).

This is the module to choose when the standard 4–8 A dimmer isn’t enough — heating elements, AC induction motors, industrial fans, large incandescent banks, or any inductive load with significant inrush current.

How It Works

Functionally identical to the standard AC dimmer: zero-cross detection + phase-cut TRIAC firing controlled by a microcontroller. The differences are entirely in the high-voltage section:

Three Dimming Methods

The original RobotDyn documentation distinguishes three AC dimming techniques the module can implement in software:

  1. Cycle skipping (burst-fire control). One or more complete sine-wave cycles are passed to the load while subsequent cycles are blocked. Good for high-thermal-mass loads like heating elements, where flicker isn’t an issue. Lowest harmonic distortion at low duty cycles.
  2. Phase-cut on each cycle. Only part of each sine wave reaches the load — the standard “leading-edge” dimming used for lamp brightness control. Maximum resolution at the cost of higher EMI.
  3. Modulated full sine signal. Generation of a modulated waveform at a different frequency (up to a few hundred Hz). Specialized — used for variable-speed AC motor control where simple phase-cut causes audible noise.

The RBDdimmer library defaults to method 2 (phase-cut) which works for the vast majority of use cases. For heater control, use method 1 manually by toggling setState() at a slow PWM rate (e.g. 1 Hz).

Pinout

PinFunctionConnect To
VCCLogic supply3.3 V or 5 V
GNDGroundGND
ZCZero-cross outputDigital input with interrupt support
PSMTRIAC gate triggerAny digital output

Same pinout as the standard 1-channel dimmer — code written for the smaller module works directly here.

Cooling Requirements

Load CurrentCooling
Up to 4 ANo heatsink required
4–8 ASmall clip-on heatsink recommended
8–16 ASubstantial heatsink required (15–20 cm² minimum)
16–24 A (peak)Forced air cooling, short-duration only

The TRIAC’s tab is electrically connected to MT2 (mains potential). Use thermal insulation between TRIAC and heatsink if the heatsink is exposed.

Compatible Loads

Works well with:

Does NOT work with:

Safety Notes

This module switches mains voltage with currents that can cause fire or injury. Required precautions:

Arduino Code Example

Identical to the standard AC dimmer — use the RBDDimmer library:

#include <RBDdimmer.h>

dimmerLamp dimmer(3);   // PSM pin
// ZC pin is fixed (D2 on Uno, D2 on Mega, D7 on Leonardo)

void setup() {
  dimmer.begin(NORMAL_MODE, ON);
}

void loop() {
  dimmer.setPower(75);  // 75% power
  delay(1000);
}

Common Uses

Where to Buy in 2026

RobotDyn production has ended. Look for compatible modules labeled “16A/24A AC dimmer 600V” with BTA16-600B or BTA24-600B TRIAC. Verify the optocoupler isolation is present (cheap clones sometimes omit it — dangerous).

Documentation