How to Use a Photocoupler “Input Current”
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Step 1. Design LED input current and input resistor RIN.
What is the input current (IF) of the photocoupler?
It is determined by (1) input power supply voltage (5 V), (2) current limiting resistor (RIN), and (3) forward voltage (VF) of LED.
From the specification example, determine the current limiting resistor and the input current (IF).
RIN=(VCC-VF)/IF=(5 V-1.3 V)/10 mA=370 Ω
Chapter V : Optical Semiconductors
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)
Principal Characteristics of Photocouplers (Trigger LED Current)
Aging Variation Data of Photocouplers
How to Use a Photocoupler
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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