Principal Characteristics of Photocouplers (Trigger LED Current)

Trigger LED current
Trigger LED current is specified for products that perform binary operation of output ON/OFF such as IC coupler of logic output, photorelay, and triac output coupler.

 “Trigger LED current” means “LED current that triggers change in the status”.

 IFT, IFLH, IFHL, etc., are used as symbols.

The trigger LED current indicated in the datasheet is the value specified by the product. For stable operation, the designer must design so that at least the trigger LED current (maximum) flows.

Principal Characteristics of Photocouplers(Trigger LED Current)

The input LED current IF is gradually increased from 0 mA,
If the output shifts to the on state at 1 mA, IFT = 1 mA.
In the following data sheet, the IF required to shift the output to the ON state
It means that the maximum value is 3 mA.

Trigger LED Current

Trigger LED current is an important item for circuit design and lifetime design.

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?
Why Are Photocouplers Necessary?
Types of Photocouplers
Types of Photocouplers (Packages)
Types of Photocouplers (Internal Structure)
Safety Standards of Photocouplers
Characteristics of Photocouplers (Current Transfer Ratio: CTR)
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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