Have few of these components (TLP582) and I need to design a test circuit to test its functionality.

Datasheet of TLP582

I have no idea how to make a circuit for this.

What should I be testing in an optocoupler?

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    \$\begingroup\$ "Testing its functionality" is a rather broad range, and so the testing circuitry could be very simple or rather elaborate. The simplest circuit that I can think of would be a voltage supply, resistor and switch activating the input side, and (together with the voltage supply) a resistor and LED on the output side. Closing the switch would, if things are set up properly, activate the LED on the output side. If that is all you are interested in, I could give you a circuit diagram. But perhaps you want more? \$\endgroup\$ Commented Jan 6, 2021 at 9:17
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    \$\begingroup\$ There are two test circuits in the data sheet. \$\endgroup\$
    – Andy aka
    Commented Jan 6, 2021 at 9:17
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    \$\begingroup\$ #Math Keeps Me Busy thank you for the info just having another doubt generally to determine a optocoupler is good/faulty what parameter must be determined or checked based on that can you suggest a circuit. \$\endgroup\$
    – Axel Blaze
    Commented Jan 6, 2021 at 16:22
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    \$\begingroup\$ @tlfong01 Thank you for the procedure can you show me a circuit diagram for it so i can understand it better please \$\endgroup\$
    – Axel Blaze
    Commented Jan 6, 2021 at 16:23
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    \$\begingroup\$ @tlfong01 Yes I can use a multimeter and have worked on few simple arduino projects I did go through electronics.stackexchange.com/questions/527190/ but will it work on TLP582 ? \$\endgroup\$
    – Axel Blaze
    Commented Jan 7, 2021 at 7:35

1 Answer 1



How can I test a TLP582 optocoupler?


Part A - Short Answer

TLP582 is similar to the popular ELP817C, except the following:

  1. TLP582 has Totem Pole output, so can either source or sink current. ELP817C other other hand, can only sink current.

  2. TLP582 has Schmitt trigger inverter in the input, while EL817C has none (not very sure) TLP 582 can be biased similar to EL817C, as described in References 1 and 2 below.

Procedures to testing TLP582

EL817C/TLP521-4 Testing Procedure

YouTube Video of TLP521-4 Testing, Using NE555 oscillator as input to blink a LED

  1. To blink a LED

    (a) Connect one end of 1kΩ resistor to 5V

    (b) Connect the other end of resistor to TLP582 Input LED Pin 1

    (c) Connect Ground to TLP582 Pin 2 to Ground

    (d) Connect one end of another 1kΩ resistor to TLP582 Output (Pin 4)

    (e) Connect ...

Note 1

I would suggest the OP to complete my circuit design, and also draw a schematic, showing the current calculations, as what is done in the EL817C in AppendixB. :)

Note 2

All the test procedures and calculations have not been proofread.


I am just a friendly hobbyist. No guarantee no nothing won't melt down or blow up.

  1. To switch a relay

Appendix B show how an EL817C optocoupler is used to switch a relay. TLp582 can be use the same circuit to switch a relay. However, there is one complication: EL817C output is open collector, so it can only be used to sink current, or Low level triggered at the front end. On the other hand, TLP582's output is is Totem Pole (Push Pull) output, so can be used to do either High or Low level triggering.

Part B - Long Answer

  1. / to continue, ...


(1) How can I increase the output current to make it sufficient for relay module?

(2) How to properly use a relay module with JD-VCC from Arduino/Raspberry?

(3) Push–pull (Totem Pole) Output - Wikipedia

(4) Schmitt Trigger - Wikipedia


Appendix A - TLP582 Datsheet Summary

tlp582 summary 1

tlp582 summary 2

tlp582 summary 3

Appendix B - EL817C and EL354 Datasheet Summary

EL817c el354 summary

Appendix C -TLP521-4 Datasheet Summary

tlp521-4 summary 1

tlp521-4 summary 2

Appendix D - Switching a relay using EL817C

el817c example

Appendix E - TLP582 Test Suggestion

Note: I don't have TLP582 to experiment with. So I am only suggesting the OP to do (1) Switch on/off a LED, (2) Blink a LED using manual jumpers, NE555 oscillator, or Arduino/Rpi C++/Python programming. I am updating Appendix E below to show how to do it using TLP512-4 or ELK817C.

TLP582 Test Suggestion

Appendix E - Using manual jumper wire as input to switch on/off LED for both TLP512-4 (Channel 1), and Sharp PC817C


  1. Both input logic power supply and output power supplied are 5V, with common ground.

  2. Input series current limiting/protecting resistor is 1kΩ, current passing through input IR LED is around 4mA.

  3. Output example load is 1kΩ in series with a LED (Common Cathode to Ground)

The wiring diagram is given below. A schematic might come later. :)

tlp512-4 and EL817C test


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