Using A Triac OptoIsolator for DC-DC Switching

Thread Starter

Keenan Rebera

Joined Apr 8, 2018
2
Hi all. I grabbed the wrong optoisolator.

I was looking for a 4N25 but instead grabbed a MOC3052 Triac that is typically used to have a DC circuit control a high-voltage AC line.

Is there any way I can switch a high voltage DC circuit with this? Slap on a diode to rectify or something?

Thanks
 

TeeKay6

Joined Apr 20, 2019
381
Hi all. I grabbed the wrong optoisolator.

I was looking for a 4N25 but instead grabbed a MOC3052 Triac that is typically used to have a DC circuit control a high-voltage AC line.

Is there any way I can switch a high voltage DC circuit with this? Slap on a diode to rectify or something?

Thanks
@Keenan Rebera
Update. Deleted as info was erroneous.
 
Last edited:

crutschow

Joined Mar 14, 2008
23,314
The triac doesn't care whether it is switching AC or DC. Assuming that all other specs are okay for your application, then yes, you can certainly switch a DC voltage on/off.
A triac may not care whether it's AC or DC to turn on but it certainly does to turn off.
The current needs to go to zero for the triac to turn off so it will turn off fine with AC, but not with DC.

So, sorry, you cannot use the triac opto to switch DC, you need a DC type such as the 4N25. :mad:
 

TeeKay6

Joined Apr 20, 2019
381
A triac may not care whether it's AC or DC to turn on but it certainly does to turn off.
The current needs to go to zero for the triac to turn off so it will turn off fine with AC, but not with DC.

So, sorry, you cannot use the triac opto to switch DC, you need a DC type such as the 4N25. :mad:
@crutschow @Keenan Rebera
I agree completely with Crutschow. As I was preparing for sleep my brain finally awoke and I rushed here only to find that Crutschow had beat me to it! Thanks!
 

Thread Starter

Keenan Rebera

Joined Apr 8, 2018
2
The DC circuit was 48 volts but it’s alright! I found a DC one on an old scoreboard circuit from the 1990’s I had sitting in my closet
 
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