Why Are Photocouplers Necessary?

In the photocoupler, the primary side (LED side) and the secondary side (light-receiving-device side) are electrically insulated. Therefore, even if the potentials on the primary side and the secondary side (even GND potential) are different, the primary side electrical signal can be transmitted to the secondary side.

In the inverter application shown in the figure on the right, a controlling unit such as a microcontroller operates usually at low DC voltage. On the other hand, IPMs and IGBTs drive loads that need high voltage such as 200 V AC. High-voltage system parts can be controlled directly from the microcomputer via a coupler.

*Various output types of photocouplers are prepared according to your needs.

Inverter Application
Inverter Application

Chapter V : Optical Semiconductors (Isolators/Solid State Relays)

Types of Optical Semiconductors
Light-Emitting Principal of LEDs
The wavelength range of LEDs
What Is a Photocoupler?
Types of Photocouplers
Types of Photocouplers (Packages)
Types of Photocouplers (Internal Structure)
Safety Standards of Photocouplers
Characteristics of Photocouplers (Current Transfer Ratio: CTR)
Principal Characteristics of Photocouplers (Trigger LED Current)
Aging Variation Data of Photocouplers
How to Use a Photocoupler
How to Use a Photocoupler “Input Current”
How to Use a Photocoupler “Output Current”
How to Use a Photocoupler “Output-Side Resistor”
How to Use a Photocoupler Check

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