Introduction: SOLID STATE RELAY WITH TRIAC
In this project we will make a solid state relay with an optotriac and a TRIAC BT136
Supplies
Step 1: SCHEMATIC DIAGRAM
We have designed the schematic diagram in the EASYEDA software where you can see all the electronic components of the solid state relay with TRIAC, it is a very simple diagram but very good for our projects.
Step 2: FUNCTIONING
Firstly, this circuit can be powered from a voltage of 3.7v to a 5v DC input to feed the optotriac or it can be powered from an ARDUINO or microcontroller and at its output we can control 220VAC loads.
when we energize the input with a constant signal of 5v we can activate the output and when there is a low signal 0v we will get the output turned off so we can control any circuit the rest is in your imagination what to do.
What are Solid State Relays (SSR)?
Solid State Relays are defined as electronic switching devices that turn loads on/off when small external voltages are applied across their control terminals. Here are some facts about them.
They typically consist of an enable switch, which is activated by applying voltage (AC or DC), and the main switch, which controls the charging current.
Unlike conventional electromechanical relays, SSRs have no moving parts and are therefore arc-free and more reliable. They also change faster and can be connected to logic circuits, among other benefits.
A solid state relay can use an optocoupler for isolation and can use a transformer. Some use a combination of both and are known as hybrid SSRs.
Solid State Relay Working Principle
To understand the principle of operation of the solid state relay, it is important that you are familiar with its circuit and its components. The solid state relay circuit is made up of an input or control circuit, a drive circuit, and an output circuit or switch.
Note that for the purposes of this article, we will be looking at the most common type of SSR, which is the optocoupler (or photocoupler) based relay.
1. Solid State Relay Input Circuit
The input circuit is where the control voltage is applied. It is also called a control circuit. The voltage can be AC, DC, or a combination of both (AC/DC). On some types of SSRs, the input is designed with +ve and -ve logic inputs, which means it can accept either TTL or CMOS connections. This is how a solid-state relay works on the input side.
When no voltage is applied, the LED turns off and no current flows through it. This means that the transistor in the output circuit is also off and no current flows through the load.
When control voltage is applied, the LED turns on, allowing current to flow through it. This, in turn, turns on the phototransistor on the output side of the relay circuit.
The control voltage of a Solid State Relay can be either AC or DC, but it must be within the specified operating range of the SSR. This is usually in the 3V to 32V range. If the voltage is too high or too low, the SSR will not work properly.
2. Solid State Relay Drive Circuit
The drive circuit is what turns on the optocoupler, which in turn turns on the transistor in the output circuit. The transistor then controls the charging current. The operation of the solid state relay at this stage is explained here.
The SSR drive normally consists of the following mini-circuits: the isolation or coupling circuit, the function circuit, and finally the trigger circuit.
The isolation coupling circuit is used to electrically isolate the control and load side of the SSR. This is important because it prevents voltage or current from flowing between the two sides, which could damage the SSR.
The galvanic isolation of the solid state relay, as the isolation circuit is also called, mainly uses an LED or infrared diode to couple or trigger the transistor on the load side. Note that some relays use transformer or transformer and LED isolation.
The function circuit may comprise rectifiers, protection, detection, and various other circuits. The enable circuit, as the name suggests, is used to activate the output circuit. The output with then, using semiconductor devices, controls the on/off function of the load.
3. Solid state relay output circuit
The Solid State Relay output circuit is the part that deals with turning on/off the power supplies of the load. It mainly consists of an output transistor or chip, a transient voltage suppressor, and may also incorporate a feedback circuit. Let's see how it works:
Upon receiving the trigger signal from the drive circuit, the high output power transistor turns on, allowing current to flow through the load. This circuit is therefore usually directly connected to the power supply of the specified load.
The components used are mainly MOSFETs, IGBTs and thyristors (SCR or Triacs). Also, the output of the solid state relay can be DC type, AC type, or both AC and DC types.
The Solid State Relay output (when classified as AC) can be either a single phase or a three phase type. These can also be zero-crossing or random-on types.
Step 3: TRIAC BT136
BT136-600E Triac 600v 4A
Bidirectional alternating current electronic switch useful to interrupt and/or continue the power supply of a device. Its versatility makes it ideal for controlling alternating currents, one of which is its use as a static SWITCH, offering many advantages over conventional mechanical switches and relays. It works as an electronic switch and also on battery.
TRIAC, 4P, 4A, 600V, TO-220
Peak Repetitive Off-State Voltage, Vdrm: 600V
Max tripping current (QI), igt: 10 mA
CT current state RMS (RMS): 4 A
Maximum representative surge current not Itsm 50 Hz Current: 27 A
Gate Trigger Voltage Max Vgt: 1.5 V
TO-220
3 pin
Step 4: ELECTRONIC COMPONENTS
- 1 TRIAC BT136
- 1 MOC3021
- 1 LED 3MM RED
- 1 RESISTOR 220 ohm 1/4w
- 1 RESISTOR 330 ohm 1/4w
- 2 BLOCK TERMINAL BLUE 2 PIN
- 1 ESPADIN 2 PIN
- 1 PCB
Step 5: PROJECT FEATURES
- CONTROL VOLTAGE FROM 3.7V TO 5VDC
- CONTROLLABLE FROM ANY MICROCONTROLLER OR ELECTRONIC CIRCUIT
- I MAX INPUT 20mA
- MAXIMUM OUTPUT VOLTAGE 660VAC
- I MAX OUTPUT 4A
Step 6: EASYEDA
This project was made in the Easyeda software as we can see the tracks and the 3D image of the project working perfectly are no difficulty
Step 7: PCBWay
PCBWAY has 10 years in the electronics industry manufacturing professional PCBs, assembling PCBs managing to satisfy the demands of all parts of the world, in addition to meeting the highest quality and delivery time standards. PCBWAY allows the manufacture of your PCBs from 5 units.
This project was carried out thanks to PCBWAY, a company dedicated to the manufacture of prototypes and professional PCBs, in addition to offering you a ready assembly service with all the components in your PCBS, complying with the established quality and delivery time standards.
We thank PCBWAY, a leading company for manufacturing and assembling professional PCBs with the highest quality, PCBWAY has fair reasonable prices, punctual shipping time and 24-hour customer service, it also offers you the option of quoting all its services in his web page. Do not think twice and start manufacturing your professional PCBs from 5 units safely.
10pcbs at $5 order them here www.pcbway.com
We thank PCBWAY for the professional pcb they provide us for this project.
GERBER PCB:
https://mega.nz/file/jQoUWZrK#Vd0hxbUOkVLMZqS9mQZtiH1vZSsl34XrOeWVdBMc6gM
