BT139-600G Triac Equivalent

Brent Hilpert bhilpert at
Sun Dec 17 15:05:51 CST 2017

On 2017-Dec-17, at 3:23 AM, Rob Jarratt via cctalk wrote:
> I have a suspicion that this component may be faulty on the input side of my
> H7826 PSU. A little tester I have does not recognise it, it is possible that
> the currents it uses are too low for this particular triac, but I am not
> sure.
> There are new ones on ebay, but I am not sure if I can trust ebay sellers to
> have genuine parts. So I would like to identify a suitable replacement. I
> have found a few suggestions for replacements, but looking at the datasheets
> many seem to have a lower peak gate power then the BT139. I am not sure what
> the critical parameters are, so I don't know how to choose a replacement.
> Can anyone suggest a good replacement for this part?

Any parameter can be critical, depending on how the device is being used.

The parameters primarily or commonly of issue with triacs are the peak blocking voltage and the RMS conducting current.

The gate power is going to be a function of the trigger circuitry, so one isn't going to know for sure without analysing the trigger circuit design.
With that said, gate circuits are generally designed for fairly low-level operation and not to be using a lot of power.

If this triac is on the input side and just used as a switch for input voltage selection, the requirements are probably pretty generic.

The Q-thousand series of triacs are (were?) pretty common:

Try comparing with the Q6015L5 (pdf.32-33).

More information about the cctalk mailing list