MOC3022 Optocoupler Testing

Thread Starter

Randa Mohamed

Joined Jun 19, 2015
25
Hello everyone
I have purchased around 15 pieces of MOC3022 and they are not working ? Not even a single one, How can I test them with an LED for example ?
 

crutschow

Joined Mar 14, 2008
24,130
How did you test them to know that they are not working?

To test those isolators that have a triac output, you need an AC source (such as from a transformer output isolated from the mains) and a DC source for the control.

If you want to use LEDs as a load then you could use two connected in inverse-parallel with a series resistor to limit the current well below the LED's maximum current rating.

The input control should be a DC voltage in series with a resistor to limit the current to about 20mA.
 

Thread Starter

Randa Mohamed

Joined Jun 19, 2015
25
@dl324 I have constructed the schematic you provided, I ignored the diac part, i set the input resistance to 300 ohms the i've connected an LED to the base pin of 2n3904 and there was no output, i removed the led and measured the output using the multimeter but it gives 0 volts
 

Thread Starter

Randa Mohamed

Joined Jun 19, 2015
25
I wanna control a triac, this is my schematic
What do you mean by "supply common" ? Sorry English isn't my first language
111.png
 
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Thread Starter

Randa Mohamed

Joined Jun 19, 2015
25
@MaxHeadRoom

Yes I've done this and when I measured the dc volts between pins 1 and 2 of the optocoupler I got a voltage drop of 1.7 as I remember. The measured voltage matched my calculations but when I tried to measure the current I got 0 amps. That's why I was suspicious.
 

dl324

Joined Mar 30, 2015
9,635
@dl324i set the input resistance to 300 ohms the i've connected an LED to the base pin of 2n3904 and there was no output, i removed the led and measured the output using the multimeter but it gives 0 volts
I meant put two inverse parallel LEDs in series with RL. When you pulse the transistor, the diac should trigger and the LEDs would indicate that.

You don't need the transistor; I copied the test circuit from the datasheet.
 
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