MOC3011 driving a 120VAC 8W LED lamp.
Fig. 1

Simple Solid State Relay for Low Power LED 120V Lamps

by Lewis Loflin

LED light bulbs feature very low power consumption thus on can use lower power switching to turn on. The perfect switch to interface directly with a microcontroller is the MOC30XX series of photo Triac opto-couplers.

In Fig. 1 I'm easily controlling a 120VAC, 650 lumen, 8-watt lamp with a single MOC3011. No other parts required on the AC side of the circuit.

The MOC3011 is rated at 250V peak at 300mW dissipation. I would not use a bulb over 10-watts at 120VAC.

I use this all the time for 24-volt AC panel lights. Would work well with NE-2 neon lamps.

Example MOC3011 circuit driving a light bulb.
Fig. 2

The circuit in Fig. 1.

The data sheet notes the MOC3011 is not intended to drive loads directly.

From the data sheet:

The MOC301XM and MOC302XM series are optically isolated triac driver devices. These devices contain a GaAs infrared emitting diode and a light activated silicon bilateral switch, which functions like a triac. They are designed for interfacing between electronic controls and power triacs to control resistive and inductive loads for 115 VAC operations.

MOC3031 type optocoupler to zero-crossing circuit.
Fig. 2

MOC3031 type optocoupler has an internal zero-crossing circuit. These can't be used in dimmer circuits the MOC3011 type.

From the data sheet:

The MOC303XM and MOC304XM devices consist of a AlGaAs infrared emitting diode optically coupled to a monolithic silicon detector performing the function of a zero voltage crossing bilateral triac driver.

They are designed for use with a triac in the interface of logic systems to equipment powered from 115 VAC lines, such as teletypewriters, CRTs, solid-state relays, industrial controls, printers, motors, solenoids and consumer appliances, etc.

While rated at 250V peak power dissipation is only 150mW. Use as specified to drive other devices.

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