17 Dec
2017
17 Dec
'17
1:05 p.m.
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:
https://www.digchip.com/datasheets/parts/datasheet/472/Q2003L-pdf.php
Try comparing with the Q6015L5 (pdf.32-33).