Switch Contact Protection - Testing it Out (2/2)

[@pieters286]

We had some issues with TVS leakage current (+20? year encoder system) Had a merry time figuring that out. Could you do a talk about aging of protection circuits?

[@FesZElectronics]

I honestly don't have too much experience with how components age, especially not semiconductors; but if your leakage current increased, rather than simple old age, I would suspect the TVS was exposed to some large transient that did not entirely brake it, but just left it in a high leakage state. Usually in an extreme cases the TVS will brake into a short circuit - thus protecting the rest of the circuit, but I guess there is middle ground between a normal clamped transient, and a completely destructive one that will just change its parameters.

[@willthecat3861]

Okay... thanks for adding the caveat about "switch contact protection" when using semiconductors (which of course don't have mechanical contacts) ... semiconductors can switch much faster than mechanical switches. There needs, IMO, to be consideration of the switching duty cycles so that just considering the peak power dissipation is not sufficient, for a robust solution... average power needs to be considered too... or the protection components will overheat, and fail.

[@FesZElectronics]

Indeed, that is why I think that although the same principles apply, with semiconductors, there are other things to pay attention to - especially when you are talking about something like a switching converter, or switching amplifiers.

[@braveheart9275]

Thanks.

[@paulpaulzadeh6172]

I used a microcontroller PIC with angular timer and triac . I hade in my design 600VA transformer with mosfet rectifier and 164000uF . Using resistor was not solution. I hade to control triac in just slightly before zero passing voltage . This way I decrease voltage peak in exact moment to have reasonable 100ohm 100w resistor. Such solution is common in microwave oven too. In my case I used it softstart for my DIY power amplifier. 😊

[@johnwetzel6200]

I'd have probably just used more switches

[@troy6882]

Or source signals going up the neg line like a 555 for a ball primer on a Airsoft gun mainly due to the large draw at half keeps tripping over the neg with director but as we no block on a neg unless to pull join they have no real use unless you got 3 to a source signal and its got to be lined correctly back to the battery it has no use the resistor is handy 😁. Wait till you get to 4 voltage regulator and trying to get a 5v carger to caps not resistance to start....O circuits.

[@chandrashekarg2073]

Hi , can you please you email ? I want to learn about ESL of plastic film capacitors high value one ? Please help