SCR or SSR

[Crusty]

Hi guys.
Just doing a bit of searching around for my controller build & see that there's two options to use as a controller.
Is the SSR a better option over the SCR if installing a PC fan in side the box?
Can you tell me what you use & why you went that way. Heat issues with the SCR over extended runs?

[RefluxEd]

An SCR (Silicon Controlled Rectifier) is a bit of a pain to use as they require a fair bit of support circuitry.

An SSR (Solid State Relay) is usually an On/Off device so you'll have no control over the heat unless you toggle it on and off at a reasonably fast interval. You'll need to get a zero crossing type otherwise you'll put hash into every AM radio in the vicinity.

There is a type of SSR that can have it's switching speed controlled with a variable resistor.
It's the best option. :smile:
I can't remember the part number at the moment I'll look at my controller when I get home and repost.

[Crusty]

SCR,
http://www.ebay.com.au/itm/181228222375 ... EBIDX%3AIT
http://www.ebay.com.au/itm/171776297008 ... EBIDX%3AIT

SSR,
http://www.ebay.com.au/itm/331411112982 ... EBIDX%3AIT
http://www.ebay.com.au/itm/321685935925 ... EBIDX%3AIT
http://www.ebay.com.au/itm/171776297008 ... EBIDX%3AIT

[Crusty]

Do you need SSR for both of these setups?

[1 2many]

Do you need SSR for both of these setups?

The top setup is easier to put together however there seems to be a reliability issue with them from what I have read.

The second setup takes a bit more to put together but seems to be more reliable. :handgestures-thumbupleft:

[rumdidlydum]

Wel thank fu.. for that haha 8-}

[1 2many]

Wel thank fu.. for that haha 8-}

Yours is good rummy, big heat sink and plenty of air flow. :handgestures-thumbupleft:

[rumdidlydum]

Dont use these. Unless you want to waste money and time or add frustration.

[1 2many]

What failed on the display?

Did it just die completely or did amps or volts die at different times. :-B

[rumdidlydum]

On both led monitors the resistor next to the white plug burnt out. I managed to resolder the 2nd lcd, when it first failed(the resistor de soldered) the 2nd time it was stuffed.

No power at all to the led,s

[1 2many]

Thanks rummy great info

This will save new builders from buying dodgy crap. :handgestures-thumbupleft:

[Crusty]

Thanks rummy great info

This will save new builders from buying dodgy crap. :handgestures-thumbupleft:

Thanks so much.
This is why I ask so many questions. This was one option I was looking at & that's now out.
I think I'll just head down the SSR route. I'm having trouble finding a 500K ohm 2W pot to suit the 500K SSR & can get the 470K or 650K.
Anyone found a 500K 2W pot anywhere?

[Fishboy]

I would go the higher resistance pot. You don't have to turn it all the way.

[Crusty]

Is this what I'm looking for?

http://www.electronicsurplus.com/claros ... ion_tabbed

[rumdidlydum]

That looks like a good one.
Remember to solder a earth to the body of it :handgestures-thumbupleft:

[RefluxEd]

Is this what I'm looking for?

http://www.electronicsurplus.com/claros ... ion_tabbed

You can't mount a knob onto the shaft, screwdriver adjustable only. :handgestures-thumbdown:

A 470K pot should work fine, there's bugger all difference.

[sp0rk]

A mate of mine that builds high end audio amps reckons (decent quality) 500K 2W pots are starting to get pretty rare, either of the 2 other options will work fine

[Triangle]

A mate of mine that builds high end audio amps reckons (decent quality) 500K 2W pots are starting to get pretty rare, either of the 2 other options will work fine

They're being snapped up buy all the Gibson guitar players! Actually you're right, old Centralab and new CTS pots are sought after due to their quality build. The new stuff is junk...but at a given resistance it does the same job, just for how long.....

BTW most pots have some pretty large tolerances anyway, so in most cases a 500K is not 500K.

[Fishboy]

Ummm one big question before I go off and get bits for this....
Log or Linear pot?? :roll:

[RefluxEd]

Ummm one big question before I go off and get bits for this....
Log or Linear pot?? :roll:

That depends on what the specs for the SSR require.
At a guess I'd say Linear.