Optocoupler triac driver circuit

The circuit is given below also plenty are available on the internet, but all are the same. The speciality of moc3021 is that it has zerocrossing ability and is driven by a triac. The pwm didnt burn out the resistor on my triac circuit, which i know because after i burned the first one on my 60w bulb, i plugged the signal pin directly into the 5v pin on the arduino, which should have told the optoisolator to turn on and stay there. They provide electrical isolation between a low voltage input and a high voltage output, whilst being able to switch the high voltage output. Isolating circuits from your arduino with optocouplers. Moc 3041 is the optoisolated triac driver that can be used to isolate ac portion of the circuit from dc operated circuit board. The figure2 depicts triggering circuit which uses optocoupler. Here is a circuit from 21008 mrdeb for a 10 led relay sequencer, that uses an moc3010 optoisolator into a triac because there is 110 volt line voltage i didnt know how to copy the thumbnail from the other thread, which is why i just put the link to the thumbnail. Introduction of optocouplers types, working and applications. In this circuit, triggering pulses are given to led of optocoupler. Triac optocoupler application this type of optocoupler configuration forms the basis of a very simple solid state relay application which can be used to control any ac mains powered load such as lamps and motors. The ac bulb dimming circuit is based on the moc3021optoisolator triac driver and bta16 triac.

How to connect optocoupler with triac to control high voltage ac load duration. Pin number 1 is the anode and pin number 2 is the cathode as per the datasheeta 330 resistor is connected in series with the anode of the ir led. This worked ok using the triac to switch the neutral line for safety. In this project, we will show how to connect an optocoupler chip to a circuit. Moc3021 light dimmer, triac bta16, zero crossing detector. This universal triac controller circuit with optocoupler solves the problem that triacs have when functioning at low temperatures triac needs higher gate current by adding a transistor at the output of the optocoupler circuit. They are semiconductor devices that combine the functionality of an optotriac or an optoscr with a power triac. I know nothing about the rs so i assumed the moc3043 was going to work for any triac. In this group of optocouplers, phototriacs, photoscrs or photodiodemosfet combinations replace the photodiodes and phototransistors described in opto coupled devices module 5, and are also readily available in integrated circuit i. High power solid state relays ssrs illustrated in fig. How to connect a relay through an optocoupler homemade. The il420 is a low input current phototriac output optocoupler consists of a gaas irled optically coupled to a photosensitive nonzero crossing triac network. Here we have a source input from a 15volt cmos circuit to source 5volt ttl circuit.

First put the multimeter selector switch in a high resistance mode say 100k, then connect the positive lead of multimeter to the mt1 terminal of triac and negative lead to the mt2 terminal of triac there is no problem if you reverse the connection. These components must be used with inductive loads such as motors, contactors, etc. A multimeter can be used to test the health of a triac. The triac is fabricated by integrating two thyristors in an inverse parallel connection. For switching, i intend to use an optocoupler and triacbased circuit. Shop onlinemoc3021 optoisolated triac driver icuse to interface electronic controls and power triacs to control resistive and inductive loads at 220v acdip6free shipping and cod available. The output of u4 monostable multivibrator goes to triac driver optocoupler moc3021 u7 which is responsible for controling the triac by applying a pulse to gate pin of triac.

This device can switch the current in either direction by applying a small current of either polarity between the gate and main terminal two. The static dvdt rating of the triac driver optocoupler and the commutating dvdt rating of the. When q2 is off, the bridge is effectively open and the triac is gated on in each halfcycle, but when q2 is on, a nearshort appears across zd1zd2r2, and the triac is off. The complete set up can be viewed in the following diagram. In this circuit above the hot side of the line is switched and the load connected to the cold or ground side. An ideal application for the optocoupler is that of interfacing the output of a lowvoltage control circuit possible with one side of its power supply grounded to the input of a triac powercontrol circuit that is driven from the ac power lines and which can be used to control the power feed to lamps, heaters, and motors. It is recommended to keep the ground side of the dc input connected to a proper earthing line. These simple optocoupler relay driver circuits can be used in variety of electronic projects.

But the circuit shown in figure 2 is completely isolated from. I am using a microcntroller to drive the optocoupler which in turn drives the gate of the triac. How to build an optocoupler circuit hacked by 4lf45t. The rest of the guide consists of application circuits. Circuit specialists carries all the varieties of diodes you could ever need everything from siliconcontrolled rectifiers to optocouplers. A 12012 ac transformer is used for giving power to circuit and for getting sine signal to find zero crossing. A triac, lamp load and a supply voltage are connected in series. An ideal application for the optocoupler is that of interfacing the output of a lowvoltage control circuit possible with one side of its power supply grounded to the input of a triac powercontrol circuit that is driven from the ac power lines and which can be used to.

The question i want to ask is how much power load i can connect to its terminal because i need to connect a 230v50a device at its output. Collections of 1949 chevy truck paint colors electronic timer with display circuit simple schematic collection wiring a transformer for low voltage lights free download wiring newe. Hi everyone, actually i have made a simple optocoupler moc3021 driven triac for lamp on off. A optocoupler also called a photocoupler, optical isolator or optoisolator is a small chip that transfers signals between two isolated circuits using light. As we know the term optocoupler optoisolater means the same that is we use light to indirectly couple to sets of circuits. So if we overrate by 5 times then it is an excellent solution for lower power controls upto 5 kilo watts. Moc3072m 6pin dip randomphae triac driver optocoupler.

An optocoupler or optoisolator chip is a chip that allows for electrical isolation between the input of the circuit and the output of the circuit. High input sensitivity is achieved by using an emitter follower phototransistor and a cascaded scr predriver resulting in an led trigger current of less than 2ma dc. Optocouplers can be ideally used for creating a perfectly isolated coupling across a low dc control circuit and a high ac mains based triac control circuit. As shown in the following circuit diagram, the relay driver may consist a npn transistor or a pnp transistor. As this triac like many others require a 50ma current to switch on i assume that at zero crossing there is not enough current to switch on this triac. Optocouplers are used for various applications which include inverters, smps, choppers, ac motor drives etc. 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.

Hi all, i have a moc3043 zero crossing triac optocoupler which i used to drive a rs triac. Broadcoms optoelectronics are designed and manufactured to meet the stringent power isolation requirements of industrial applications. The triac consists of two inverse parallel connected monolithic scrs. Can anyone suggest which specific triacs will work with a zero crossing triac optocoupler driver. Moc3021 is a zerocrossing triac driven optocoupler or optoisolator. A triac is a bidirectional, threeterminal dual, backtoback thyristor scr switch. To switch the ac current to the lamp, we have to use an optocoupled triac, lamp and a diac is shown in circuit below. Diff between triac, scr, optoisolator w triac, and ssr. For more on the above optocoupler see moc30xx series optoisolator pdf file. Triac optocoupler circuit electrical engineering stack exchange. Optocoupler, phototriac output, zero crossing, high dvdt. Controlling a triac with a phototriac application note. Our schottky diodes are range from 20 prv, 25 ifm surge, and 1 amp up to 40 prv.

How to use optocoupler and triac to control ac load. The cycle time of contactors must be 2060 seconds to make it last long. I want to operate a relay through optocoupler as shown in the circuit. Advantages of optocoupler disadvantages of optocoupler. The multimeter will show a high resistance reading. The circuit shown in figure 1 will drive the relay through optocoupler in same circuit with same power supply. The chip has an led and an optically active scr in a common. It doesnt work and since i dont know what to expect, it would be great to get some troubleshooting help. However, during the commutation of the power triac in application where the load is inductive, both triacs are subjected to fast rising voltages. Review ac relay circuits optocouplers triacs youtube. Triac and scr output photocouplers are also known as triac and scr output optocouplers. Using a thyristor triac to switch ac line power duration. It helps to prevents the damage of dc circuit when there is an accidental leakage of ac in triac controlled lamp driver circuits moc 3041 has built in zero crossing sensing zcs for on off applications. Triacs are widely used in applications such as lamp dimmers and motor speed controllers and as such the diac is used in conjunction with the triac to provide fullwave control of the ac supply as shown.

For switching, i intend to use an optocoupler and triac based circuit. In addition to triac drivers and rectifiers we carry germanium, zener, schottky, and highspeed switching diodes. Hello ive constructed a triac circuit using the suggested circuit on the triac drivers data sheet. As stated above, the diac is commonly used as a solid state triggering device for other semiconductor switching devices, mainly scrs and triacs. Q2 is driven via the optocoupler from the isolated external circuit, and the triac is on when sw1 is open and off when sw1 is closed. There is a pulsing output from the up that goes to the optocoupler triac driver moc3023 that i can see as there is an led to reflect. A basic optocoupler uses a led and a phototransistor, the brighter the led the more c. Active discontinued at digikey last time buy obsolete. Principle of power triac drive with of a phototriac phototriac load led r1 iload igt vt it ift vphoto vline starting with power triac and phototriac in off state, ac voltage is. Optocoupler, phototriac output, zero crossing, high dvdt, low input current il410, il4108 vishay semiconductors description the il410 and il4108 consists of a gaas irled optically coupled to a photosensitive zero crossing triac network. The moc3021 has actually total of 6 pins but pin number 3 and pin number 5 are not used.