Actual wiring of the optocoupler module
An optocoupler module is wired by connecting the input LED to a signal source with series resistor and the output phototransistor to a separate power domain, ensuring complete electrical isolation between input and output.
Input Side Wiring
The input side of the optocoupler contains an infrared LED. To wire it correctly:
- Connect the anode of the LED to the positive voltage of your input signal (VCC) through a current-limiting resistor to prevent overcurrent.
- Connect the cathode to the input ground (GND) of your signal source.
- The input is active LOW, meaning the LED turns on when the input pin is pulled to GND, causing the LED to emit infrared light and activate the output phototransistor.
- Many modules include an indicator LED that lights up when the input LED is active, helping with troubleshooting .
Output Side Wiring
The output side contains a phototransistor that responds to the LED light:
- The collector of the phototransistor connects to the output voltage (VCC) through a pull-up resistor if not already included on the module.
- The emitter connects to the output ground (GND).
- The output is typically open-collector, meaning it can only sink current when active. When the input LED is on, the phototransistor conducts, pulling the output LOW; when the LED is off, the output is HIGH due to the pull-up resistor .
- Ensure the output VCC and GND are completely separate from the input side to maintain isolation. Do not connect input and output grounds together .
Optional Jumper or Pull-Up Configuration
Some modules include a jumper or solder bridge to enable or disable the on-board pull-up resistor on the output side:
- If your circuit already has a pull-up, you can disable the module's resistor.
- If not, enable the pull-up to ensure proper HIGH output when the phototransistor is off .
Summary Wiring Steps
- Connect input anode → series resistor → input VCC.
- Connect input cathode → input GND.
- Connect output collector → output VCC (through pull-up if needed).
- Connect output emitter → output GND.
- Keep input and output power domains isolated.
- Verify jumper settings for pull-up resistor if applicable. This wiring ensures the signal is transferred optically without electrical connection, protecting sensitive circuits from voltage spikes, noise, or ground loops .
Information How Optocouplers Work
FREE COURSE!! Learn about optocouplers. We''ll look at how they are used to control circuits, how they work and
Information How to Build an Optocoupler Circuit
In this project, we will go over how to build an optocoupler circuit so that we can create electrical isolation of the input and output of a
Information Arduino Tutorial: HY-M154 / 817 / PC817 Optocoupler
This tutorial gives an introduction to the HY-M154 / 817 optocoupler module. Moreover, a
Information How to Use Relay with optocoupler: Examples, Pinouts, and Specs
Learn how to use the Relay with optocoupler with detailed documentation, including pinouts, usage guides, and example projects.
Information Optocoupler Circuits, Working, Characteristics, Interfacing
The attached second design shows optocoupler module designed to respond to reflected IR signals. The IRED and
Information How Optocouplers Work and How to Use Them
In this episode, we look at the optocoupler, or optoisolator, as it''s also known. This little
Information Optoelectronics: Optocouplers
Isolation refers to the separation between two systems or voltage levels, while insulation refers to the actual medium
Information Optocoupler Tutorial for Beginners
An optocoupler (or opto-isolator) is a component that transfer signals between circuits using light. In this guide, you''ll
Information What is Optocoupler and How it works?
What is Optocoupler and How It Works As we have already learnt about transistors, an ideal transistor will not allow
Information Optocoupler | Explore Our Workshop | Jameco Electronics
Understand what an optocoupler is and how it works at our electronics workshop at Jameco Electronics. Explore tutorials on how
Information Optocoupler Circuits | Nuts & Volts Magazine
Simply described, an optocoupler device is a sealed, self-contained unit that houses independently-powered optical (light) Tx and Rx
Information ANO007 | Understanding Phototransistor Optocouplers
In order to design a functionally robust and reliable application with optocouplers, it is essential to understand not only the device''s
Information What Is Optocoupler and Its Application with Examples
An optocoupler is a semiconductor device that transmits an electrical signal between two
Information The Ultimate Optocouplers Guide: Isolation, Types, and Applications
Our complete optocouplers guide covers what they are, how they work, the different types, and key applications.
Information How to Design Relay Module using Optocoupler || Relay Module Circuit
"In this video, you''ll learn how to design a relay module using an optocoupler, perfect for
Information Optocouplers Guide: Understanding Types, Applications, and
By understanding these benefits, you can see why optocouplers are a vital part of any optocoupler design guide. They
Information Optocoupler Tutorial and Optocoupler Application
What is an Optocoupler? An optocoupler (also called an opto-isolator, photo-coupler, or optical isolator) is a solid
Information Arduino Tutorial: 2-Channel Optocoupler Relay Module
The optocoupler is extensively utilized in computer terminals, thyristor control devices, measuring
Information Optocoupler Operation
Module 5.1 Optocoupler Operation What you´ll learn in Module 5.1 After studying this section, you should be able to: Describe
Information PC817 Optocoupler Module User Guide | Wiring & Setup
Complete PC817 optocoupler isolation module guide. Covers 3.6V–30V wiring, jumper
Information Optocoupler Isolation Board DST-1R4P-N (+ Arduino
There are two terminal block to wire GND and VCC to the board. Moreover, next to the
Information Interfacing PC817 4-Channel Optocoupler Module with
Learn How to interface a PC817 4-Channel Optocoupler Module with Arduino. using PC817
Information Optocoupler Tutorial and Optocoupler Application
Optocoupler Tutorial about how Optocouplers and Opto-isolators use light to electrical isolate its input signal from its
Information Optocouplers in Electrical Isolation and Signal Transmission
Overview: This article explores optocouplers, which are important for electrically isolating circuits and enabling signal
Information Using Opto Couplers
The main purpose of an optocoupler interface is to completely isolate the input circuit from the output circuit, which normally means
Information Optocoupler Circuits, Working, Characteristics, Interfacing
Optocouplers become an effective replacement for relays, and for transformers for interfacing digital circuits stages.
Information How to Use an Optocoupler to Pass Signals Between Controllers at
How to Use an Optocoupler to Pass Signals Between Controllers at Different Voltages: This tutorial makes use of the 4N25
Information How to Connect a Relay through an Opto-Coupler
The following concepts show how a relay driver can be configured with an optocoupler using transistors. As shown in the following
Information How to make the connections to the 1 channel optocoupler relay module?
I want to light a bulb connected to the socket by using an 1 Channel Optocoupler Relay Module which accepts an input of 5V. From