![]() The optocoupler is also used as a fuse with more advanced features than a fuse. If you need to drive a high voltage motor using the command with a microcontroller then the optocoupler will provide a switching system with the full electrically isolated connection between motor and microcontroller output. Protection from the highly sensitive circuit from a high voltage circuit and– In this, you can switch ON or Switch OFF A 220V AC Load by using 5V DC operated signal supply. Applications of optocouplers There are the following main uses of the optocouplerĪllow you to use small digital signals to control larger AC voltages.- Solid State Relay is the best example of this. There are various types of circuits in digital communication systems, power supply systems,s, and other hardware systems designed using the optocouplers by engineers because it makes high sensitivity, for protection, most convenient fast switching and highly responsive with a digital signal, etc. Input light and output current relationship of photodiode optocoupler is good in most audio and some digital signals even though the output signal amplitude of photodiode is very less than output provided by the phototransistor. But some distortion may occur at the high frequencies. ![]() The transistor output varies to amplifying as the light beam gets on its BASE. Although phototransistor optocoupler can pass the analog audio signals at wide frequencies by varying the LED beam that goes to the BASE of the phototransistor. ![]() Photodiode Optocouplers are better than phototransistor optocouplers in a linear relationship between the current and the light. Photodiode vs Phototransistor optocouplers This can be used in a switched-mode power supply (SMPS) or controlling different circuitry where error detection at the output is required. Illumination of LED is varied or controlled with a sample of voltage or signal, then the phototransistor also provides variable conduction to the output. In this mode, LED will get a pulse of signal with a variation. The motor will ON or OFF completely in this mode. For example in motor drive using a microcontroller, the motor needs high current and high voltage. This mode is used where needs to protect the microcontroller pins from the high voltage of the output circuit. In saturation mode LED will ON or OFF so, the output transistor is fully off or fully ON, which means conducting or non-conducting mode. Saturation and linear Mode operation of the optocoupler Saturation mode In SMPS or any power supply circuit optocoupler may use to detect the varying DC sample voltage of output and give feedback to input to control the power supply with the maintain the complete electrical isolation between input and output circuit. Microcontroller output is directly connected with the input of LED of the optocoupler, and the Phototransistor is connected with the output component like Relay or Triac for 220v Ac connection with the Motor. In this case, we cannot directly connect both. If we need to connect a 220v AC Motor that is controlled by a microcontroller or Arduino etc. Here computer system circuit and Motor controlling device is fully electrically isolated, there is no interference of electrical signal. Optocoupler is commonly used where A computer system or any digital system needs to control or drive a motor or control the high voltage devices. Optoucpler IC uses an LED optically coupled to a phototransistor, photodiode, or Photo TRIAC in a single package ![]() Opto-Triac (photo-Triac) is also used at the place of Photo-transistor in optocoupler for direct AC supply controlling at the output. The electrical isolation is very high generally 10KV or higher. There is non-conductive material and space is transparent between LED and Photo-transistor. Both input and output circuit is fully Electrically isolated. Here the input circuit connected only with the LED pins of the optocoupler, Output circuit connected with the phototransistor. When the power is given to led, the led emits the light and that light falls on the BASE of the phototransistor, After falling light on the base of the phototransistor this will activate and the output circuit connected with the transistor can be controlled. And the right side is a phototransistor, this phototransistor is sensitive to light. The left side is a led connected through pin 1 and pin 2. This is the internal circuit mechanism of an optocoupler. in this system, the Input Light is proportional to the current at the output. when light is emitted by an LED and that light hits on the photosensor (Photodiode, Phototransistor, PhotoTriac) then the photosensor starts to flow the current. An optocoupler consists a Transmitter as IR LED and a Receiver as a photosensitive component.
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