What is a MOC3021?

What is a MOC3021?

MOC3021 is a non-zero crossing based optoisolator consists of gallium arsenide infrared emitting diodes, optically coupled to a silicon-based triac. It is having internal TRIAC installed which gives it a capability to control any external switching devices like HIGH POWER TRIAC, MOSFETS, and Solid States Relay.

How does MOC3021 work?

The MOC3021 comes in an internal light-emitting diode and a TRIAC based light activating based transistor. This optocoupler provides protection from HIGH resistive and inductive loads. MOC3021 Optocoupler work on the IR based and it keeps any kind of current to flow towards the circuit.

What is the use of optoisolator?

When used correctly, an Optocoupler can effectively: Remove electrical noise from signals. Isolate low-voltage devices from high-voltage circuits. Allow you to use small digital signals to control larger AC voltages.

What does a triac do in a circuit?

The TRIAC allows current to flow in either direction with flow changing with the polarity of the gate voltage. The gate voltage can be derived from the AC voltage applied to the TRIAC’s load terminals.

Why do you need optocoupler?

Optocouplers are often used to reject back EMF, noise, and electrical surges from entering an MCU circuit. Optocouplers create a safe connection between high voltage equipment and microcontrollers with a means of complete electrical insulation.

What is the role of optocoupler?

Need to protect sensitive, low-voltage components and isolate circuits on your PCB? An Optocoupler can do the job. This device allows you to transmit an electrical signal between two isolated circuits with two parts: an LED that emits infrared light and a photosensitive device which detects light from the LED.

Why is optocoupler used?

What is a zero-crossing detector?

A zero-crossing detector or ZCD is one type of voltage comparator, used to detect a sine waveform transition from positive and negative, that coincides when the i/p crosses the zero voltage condition. The applications of the Zero Crossing Detector are phase meter and time marker generator.

What is the power output of moc3021?

The speciality of MOC3021 is that it has Zero-Crossing ability and is driven by a Triac. Since the output is driven by a TRIAC we can drive loads upto 400V and the triac can conduct in both directions hence controlling AC loads will not be a problem.

What is moc3021 optocoupler?

The MOC3021 is a Zero-Crossing TRIAC driven Optocoupler or Optoisolator. As we know the term Optocoupler/optoisolater means the same that is we use light to indirectly couple to sets of circuits. The speciality of MOC3021 is that it has Zero-Crossing ability and is driven by a Triac.

How do I use the moc3021 to switch the TRIAC?

The MOC3021 can be used to switch loads by simply switching the LED on or off, or we can also use PWM signals to switch the LED and thus the TRIAC. When the TRIAC is switched by using PWM signals, the output voltage across the load can be controlled by controlling the speed/brightness of the load.

How to use moc3021 in automatic light on method after daylight?

In this example, we are going to use the MOC3021 in automatic light on method after daylight. We are going to use a transistor, TRIAC, lamp, 220 AC, resistors and an LDR. In this circuit, LDR will be used to detect the sunlight and moc3021 will be used to turn on and off the lamp through the TRIAC.