Optocouplers are commonly found in most electric and electronic devices. If you are manufacturing an electronic device or appliance, you may consider adding an optocoupler. In this guide, we are going to look at everything that you need to know about optocouplers.
What is an optocoupler?
An optocoupler is a semiconductor optoelectronic device that performs the task of optically separating an electrical signal from another device or a source. It can be used as a light-controlled switch, Opto sensor, and optically controlled transistor.
The optocoupler has two basic components: an LED that emits light signals and a light detector that optically reads the signals emitted by the LED. The optocoupler emits optical signals using LEDs so it can be used in places where there is no electrical connection possible.
When an optocoupler is used as a switch, currents are transmitted to another device or circuit by way of an infrared signal.
What are the components of an optocoupler?
The optocoupler has the following components:
– An Opto LED (Optical Transmitter) is an optoelectronic semiconductor and emits light.
– A phototransistor (optical receiver or optoelectronic semiconductor). The phototransistor receives the optically transmitted signal from the Opto LED and makes it appear as an electrical current. It can be used as a switch to turn devices on and off depending on the received optical signals.
How does optocoupler work?
Let’s now look at the working principle of an optocoupler.
The Opto LED optically transmits signals to the phototransistor using infrared light. The optocoupler is used in applications where there is no electrical connection possible.
When an optocoupler is used as a switch, it allows current to pass through by turning on and off depending on the received optical signal intensity.
Advantages of optocouplers
Are optocouplers good? Why should I buy optocouplers?
One way transmission of signals
Optocouplers optically transmit signals. They do not normally pass through any material, they will not be subject to signal loss or interference that might occur when passing through other media like metal wires.
Optical isolation
Optoelectronic semiconductors are optically isolated from each other, preventing them from affecting each other when they are in operation. This is useful if the optocoupler is meant to operate a device which could pose a risk if it operates before it’s ready.
For instance, a lamp circuit optocoupler prevents the lamp from engaging until the circuit is switched on using an optocoupler because it does not pass current via electrical relays or magnetic field which would cause undue interference and damage to lamps.
Low cost
Optocouplers optically transmit signals, so optocouplers are cheaper than opto-isolators or opto sensors. They optically transmit signals so they do not have the extra added cost of a converter chip.
Less noisy
Most optocouplers optically transmit signals therefore they are not prone to electromagnetic noise. They optically transmit signals so there is no need for an electrical connection thus lessening the risk of interference.
Durable
Optocouplers optically transmit signals, optoelectronic semiconductors are very durable. They do not break down easily they can last longer than opto-isolators or opto sensors. They will withstand the vagaries of the weather and position changes like vibration and shock which cannot be said for optoisolators or opto-sensors.
High stability
Optocouplers are known for their stability. They optically transmit signals therefore it is very difficult for them to change the properties of the signal. Their stability makes them ideal in applications that require precise and accurate measurements like PCB manufacturing and automation control systems and they are also preferred in harsh environments.
Resistant to electromagnetic interference
Optocouplers do not normally pass through any material and therefore the risk of electrical interference is very low. They optically transmit signals so they are not affected by electromagnetic noise.
Widely available
Optocouplers are widely available on most sites for sale and online, therefore it is easy to find them or buy them.
Ease of use
Optocouplers are easy to use. They do not require drivers unlike some other opto sensors like the optical sensor. The phototransistor is easy to interface with an existing circuit or system.
Convenient
Optocouplers come in small sizes, making them very convenient and easy to install on PCBs and light panels.
Limitations of optocouplers
Here are some limitations of using optocouplers:
They are not good for high-frequency applications. They cannot carry fast signals.
They are limited to carrying low current load only because the transistor used in phototransistors is a low power one. This makes them unsuitable in situations that require high power transmission of signals like LEDs and light panels.
They are prone to degradation over time.
Optocouplers are not completely immune to electromagnetic interference. But their performance is superior to other types in this category like optoisolators, optical sensors, and phototransistors.
They require a well-designed driver circuit in order to work well over time, therefore one must have a high level of understanding when using them.
However, you can work around these limitations by buying quality optocouplers in China.
How to use optocouplers
How do I start using the optocoupler?
Use an optocoupler as part of a circuit or system that requires transmission of the signal without any electrical connection.
For instance, you need to connect the power source of an appliance to its control unit to operate it.
-Cut a hole through the body of the appliance and insert a bulb.
-Put together the power source and control unit with wires that reach into or pass-through this space containing the bulb. This will be a physical connection between them.
-Ground the control unit by attaching a wire from one terminal to the ground.
-Ground the power source by attaching a wire from one terminal to the ground.
-Connect them with an optocoupler, in this case, but the base of the phototransistor through this space and connect its other terminal to the ground.
-The power source converts light into electrical energy and passes it on to the control unit via the optocoupler.
-The control unit converts the electrical energy into a mechanical action for instance motion, rotation of a shaft, or some other type of motion.
How optocouplers work in various applications
An optocoupler, also known as an optoisolator, optocoupler, or optoisolator is a device that optically separates an electrical signal from another source. It can be used as a light-controlled switch, opto sensor, and optically controlled transistor.
Here are the main types of optocouplers that you should know:
An optical to electric optocoupler
This optocoupler transmits signals from one optoelectronic device to another optoelectronic device which is optically isolated from each other. The Opto LED transmits a signal optically and the phototransistor receives it optically, making it appear as an electrical current. It can be used as a switch to turn devices on and off depending on received optical signals.
An Opto sensor optocoupler
This optocoupler optically transmits signals from various sensors to an optoelectronic device which is optically isolated from each other so there can be no electrical connection, preventing any kind of interference in the optoelectronic circuit.
An optically controlled transistor optocoupler
This optocoupler optically transmits signals from one optoelectronic device to another optoelectronic semiconductor which is optically isolated from each other.
The Opto LED optically transmits a signal and the phototransistor optically receives it. The phototransistor then converts it into an electrical current that can be used to control a load.
An optically controlled relay optocoupler
This type of optocoupler uses an LED to transmit signals from one circuit terminal to another via the light-emitting diode which is controlled by a remote station or electronic signal. The LED is enclosed in a plastic case that has a light-transmitting capacity almost as high as that of glass.
Optocoupler which uses Photo TRIAC
This type of optocoupler uses a photo triac which is a semiconductor device similar to the thyristor. It changes state when light falls on it, triggering the optocoupler. Like thyristor, it is used as a switch that turns on when light falls on it and off again when the light source stops emitting light.
Optocouplers that use phototransistors
This type of optocoupler uses phototransistors to receive optical signals. The Opto LED emits an infrared or visible band light that is then received by the phototransistor.
Opto-coupler which uses Photo SCR
This type of optocoupler uses photo SCR (thyristor) to turn on and off the current in the load. For this purpose, it is connected in parallel with a diode that protects it from an inductive load. Photo SCR turns on when light falls on it and switches off when the light source stops emitting light.
Opto-couplers which use Photo triode
This type of optocoupler uses photo triodes to transmit light signals. The light emitted by the LED is then transmitted through a phototube that converts it into an electrical signal. It then passes on the electrical current to the load.
Applications of optocouplers
So, where are optocouplers used?
The most common application of optocouplers is in linear motor speed control. It is used to control the current flow through either an led or a lamp.
For starters, you can use it as your night light using no wiring at all. And if you are looking for advanced applications, here are some that will interest you:
Optocouplers in LED lamp
This optocoupler is used to turn an LED on and off in a lamp or a flashlight. The light that comes from the LED enters one side of the optocoupler via an infrared emitter, which activates the Triac switch when it receives light.
The triac switches on when it receives current from a power source and this makes the lamp turn on automatically. When the light stops penetrating the infrared emitter, the triac turns off automatically.
Optocouplers in an automobile
This is used to control the speed of a car engine by measuring the speed with a wheel sensor and passing this information via an optocoupler to an led speedometer which provides the driver with this information.
Optocouplers are also used in many other applications like power tools, washing machines, ovens, etc.
Tips for buying optocouplers
When buying an optocoupler, you should check the following things before settling on one:
-Type of signal it is used with:
You should check what type of signal you want to optically transmit. Is it an analog or digital signal?
-Light source:
Is the light source that is needed for use with your optocoupler LED, or TRIAC, etc.?
-Compatibility:
Make sure it is compatible with the other component that will be used with it.
Brand: Always go for a reliable brand that you can trust to buy optocouplers from. Ensure the supplier is reputable and known for good products to avoid disappointment. Check customer reviews before buying a product this way. Go for high-quality, recommended brands even if they cost more, as they last longer.
Availability of technical details:
Check whether the manufacturer gives you enough information to make contact with them in case you encounter any problems. Consider getting optocouplers from manufacturers who provide this kind of support, which is vital if you want to avoid downtime or delays caused by not being able to communicate easily with the seller.
Price: Check whether you can afford to purchase the optocouplers and how much it costs for different models.
Suitable for your application’s environment:
Make sure the optocoupler is suitable for your application’s environment. Most optocouplers are not watered resistive and can be damaged by extended exposure to high temperatures.
Miniaturization desired. Optocouplers can be surface mount, hermetic or through-hole devices
The priority of power dissipation and/or isolation. If you are using a low voltage signal optocoupler, you can choose between a high-power device with clamping diodes or a lower power pure linear design. On the other hand, if you want to transmit a high voltage signal, then you can choose between isolation and non-isolation.
ICRFQ: Reliable Optocoupler Supplier In China
Optocouplers are an essential part of controlling electrical circuits. It is cheap, easy-to-use, reliable, and accurate. With this component, you can easily control the flow of current into a system that needs good control over current management.
In case you want to buy optocouplers for your device or appliance, consider buying from ICRFQ. We are one of the leading suppliers in China for this product. We manufacture high-quality optocouplers that will be suitable for your appliances or devices.
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