Last Updated on October 22, 2023 by Kevin Chen
The PC817 optocoupler is an electronic component that consists of a light-emitting diode (LED) and a phototransistor.
It is used to isolate one electrical circuit from another, while still allowing the two circuits to communicate.
The PC817 optocoupler is typically used when galvanic isolation is required, such as when connecting digital signal lines between two circuits.
In this guide, we are going to discuss everything you should know about PC817 optocoupler.
You will also learn the tricks and tips for buying this semiconductor device in China.
Overview of PC817 Optocoupler
As we have described above, PC817 IC is a photocoupler that comprises of a transistor and IR diode.
It is used for electrical isolation between two circuits. The PC817 optocoupler is an inexpensive, 4-pin device that isolates a low-voltage control signal (from a microcontroller, for example) from a higher-voltage, higher-current signal (such as a motor drive circuit).
The PC817 optocoupler can handle up to 50mA of output current, and its input is capable of operating with a voltage up to 30V.
The PC817 optocoupler is also capable of rejecting transients and noise on the input side, which makes it ideal for use in noisy industrial environments.
Additionally, the PC817 optocoupler has a wide operating temperature range, which makes it suitable for use in extreme conditions.
How does PC817 Optocoupler work?
A typical PC817 optocoupler comprises of an infrared LED and a phototransistor, which are optically coupled together in the same package.
The LED emits light when a voltage is applied across its terminals and the phototransistor detects the light emitted from the LED.
When the LED is illuminated, the phototransistor is activated and a current flows through its collector-emitter terminals. This current can then be used to trigger other circuits.
When an optocoupler is integrated in a circuit, the LED is connected to the input voltage source while the phototransistor is connected to the output circuit.
When the input voltage is applied, the LED emits light which is detected by the phototransistor, activating the output circuit.
This allows the output circuit to be controlled by the input voltage without any direct electrical connection.
The PC817 optocoupler can also be used for electrical isolation between two circuits, as it allows for electrical signals to be transferred between two circuits without any direct electrical connection.
This type of optocoupler is commonly used in motor control circuits, power supplies, and industrial automation systems.
PC817 Optocoupler Pin Configuration
The following is the pin configuration of the PC817 optocoupler:
Pin 1: This is the anode of the infrared LED. It is connected to the positive voltage of the input circuit.
Pin 2: This is the cathode of the infrared LED. It is connected to the negative voltage of the input circuit.
Pin 3: This is the collector of the phototransistor. It is connected to the positive voltage of the output circuit.
Pin 4: This is the emitter of the phototransistor. It is connected to the negative voltage of the output circuit.
The figure below depicts the full pin configuration
Features of the PC817 Optocoupler
Now let’s look at the key features of this IC
-Number of pins: The PC81 IC has 4 pins.
-Output: The input of the PC817 IC Optocoupler is typically a digital signal, while the output is typically an analog signal.
-Input Voltage Range: The input voltage range of the PC817 IC Optocoupler is typically between 4-40 volts.
-Output Current: The output current of the PC817 IC Optocoupler is typically between 0.5-7mA.
-Isolation Voltage: The isolation voltage of the PC817 IC Optocoupler is typically between 500-5000Vrms.
-Package: The PC817 IC Optocoupler is available in a wide selection of packages, including DIP, SMD, and others.
-Internal protection: The PC817 IC Optocoupler features internal protection against overvoltage, overcurrent, and reverse polarity.
-Additional resistor: The PC817 IC Optocoupler may require an additional resistor to ensure proper operation.
PC817 Optocoupler Technical specifications
Now let’s look at the technical specs of this IC optocoupler.
-Maximum collector current :50 mA
-Isolation voltage :5000 Vrms
-Rise time :18 µs
-Fall time: 18 µs
-Operating temperature range :
-55°C to 100°C
-Package : DIP-4
-Cut-off wavelength : 800 nm
-Cut-off frequency: 80 kHz
-Internal resistance: 100 ohms
-Collector-emitter saturation voltage: 0.2 V
Applications of PC817 Optocoupler
Here are the common applications of this optocoupler IC.
Here, the PC817 Optocoupler can be used to isolate a circuit from external interferences or spikes. Such circuits are commonly used in applications such as
- Switch mode power supplies
Signal Level Conversion
The PC817 Optocoupler can also be used for converting the level of a signal from one voltage level to another. This is especially useful in applications such as
- Interfacing two different types of logic circuits
- Interfacing digital and analog signals
- Isolating signals in automotive systems
The PC817 Optocoupler can be used in protection circuits such as
- Over current protection
- Over voltage protection
- Short circuit protection
- Surge protection
Noise coupling circuits
The PC817 Optocoupler can be used in noise coupling circuits to reduce the effect of noise on a sensitive circuit.
This is especially useful in audio applications.
The optocoupler can be used to control the power supply to a load.
This is commonly used in applications such as motor control and lighting control.
What should I look for in a PC817 optocoupler?
When selecting an optocoupler, you should consider the following factors:
- Input-Output Voltage Rating: Be sure to choose an optocoupler with an input-output voltage rating that meets the needs of your application.
- Response Time: The response time of an optocoupler will determine how quickly it can detect changes in light.
- Isolation Voltage: Make sure to select an optocoupler with an isolation voltage rating that is greater than the maximum voltage your circuit will be exposed to.
- Operating Temperature: Consider the temperature range in which your optocoupler will be used.
- Number of Channels: Determine how many channels your optocoupler needs to support.
- Isolation Resistance: Select an optocoupler that has a high isolation resistance to prevent current leakage.
- Power Consumption: Choose an optocoupler with low power consumption to reduce the overall power usage of your device.
Using all these tips, you can contact a reliable PC817 optocoupler supplier in China and place your bulk order. Meanwhile, we at ICRFQ are always ready to fulfill your needs for such electronic components.
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