quick question on what diode will work (ac wire to fan temp switch)

[Eddo Rogue]

I was wondering what diode I can use for the line to my temp switch that will switch on my efan when I switch on the ac.

In my efan thread, RonD told me:

You would be fine with an 1N5820 Diode, 20v 3amp, way more than you need, but cost difference is negligible
6 of them run about $2 or under $1 each if you can get just 1

1N5820 DO-201AD is the type and package

I couldn't find this exact one on ebay, which would be the easiest route of purchase for me. I did find a 1.5amp, will that be enough?

Can I just go with any that is 20v and 3amp?

 

[Dirtman]

I uhh... RonD knows all electrical but don't see why a diode is required? Diodes are one way switches for electrical current so it doesnt flow backwards. A relay off the AC 'command on' line wire, seperate from the thermostatic switch should work. It would come on either with the temp sensor, or if the temp sensor isnt high enough automatically run when AC is on and vice versa. Dont understand why a diode is needed but I didnt read the original post from RonD. I'd take his advice over anything anyone says including myself lol.

Are you confusing a diode and relay?

 

[Curious Hound]

I uhh... RonD knows all electrical but don't see why a diode is required? Diodes are one way switches for electrical current so it doesnt flow backwards. A relay off the AC 'command on' line wire, seperate from the thermostatic switch should work. It would come on either with the temp sensor, or if the temp sensor isnt high enough automatically run when AC is on and vice versa. Dont understand why a diode is needed but I didnt read the original post from RonD. I'd take his advice over anything anyone says including myself lol.

Are you confusing a diode and relay?

He split this out of his other thread on the subject, where RonD mentioned a circuit design that would benefit from the use of a diode. This post by itself is easy to get out of context.

 

[Dirtman]

He split this out of his other thread on the subject, where RonD mentioned a circuit design that would benefit from the use of a diode. This post by itself is easy to get out of context.

Fair enough, ignore me follow @RonD sorry. Ron knows his stuff.

 

[Curious Hound]

Fair enough, ignore me follow @RonD sorry. Ron knows his stuff.

I'm not trying to say you're wrong. It has to do with an idea Ron had for wiring the circuit differently. And in that particular abnormal case, it made sense. In my opinion, it would be better to just find the problem and fix the circuit the way it was designed. But there are alternatives.

 

[RonD]

The "problem" was how to activate 1 relay(fan's power relay) with TWO separate 12volt triggers

So not a ground activation relay setup, not that it matters

The two triggers are
Temp switch, 12v out
AC clutch wire, 12v out

You need to connect these two 12v out wires to the 1 relay so either can turn on the Fan

"Problem" is the AC clutch, i.e. when temp switch heats up and closes, the 12v OUT goes to the fan relay AND the AC Clutch since its also connected to same pin on relay
So AC Clutch would engage any time Temp switch activates the fan

"Problem" doesn't occur the other way, the temp switch doesn't care if its get 12v from AC clutch on its OUT wire

So you need a way to prevent 12v from temp switch from turning on AC Clutch
You could use another relay
But a diode on the AC Clutch wire at the relay would be easier and cheaper, so the 12v from the Temp switch can't flow out on the AC Clutch wire to activate the clutch

 

[Eddo Rogue]

Yes what RonD said, and is saying now lol...I get why I need one (for the most part). I just wanted to know what else would work if I couldn't find the exact diode mentioned, like for example if instead of 3 amps,1.5 amps is enough, or if it has to be 20v...maybe my search engine sucks, but seems I can find every combo but the one specified... at least on ebay. I'm a diodiot.

 

[Dirtman]

I'm not trying to say you're wrong. It has to do with an idea Ron had for wiring the circuit differently. And in that particular abnormal case, it made sense. In my opinion, it would be better to just find the problem and fix the circuit the way it was designed. But there are alternatives.

I am completely happy to be called wrong by RonD. Or you for that matter. you guys know your stuff.
I

 

[Eddo Rogue]

I am completely happy to be called wrong by RonD. Or you for that matter. you guys know your stuff.
I

Naw you made Ron elaborate, which he didn't seem to mind doing, and I learned something reading it. So you did help, if not by accident...like that guy who trips and spills his drink on a busty lady wearing a white shirt, everyone wins! (almost)

 

[Dirtman]

Naw you made Ron elaborate, which he didn't seem to mind doing, and I learned something reading it. So you did help, if not by accident...like that guy who trips and spills his drink on a busty lady wearing a white shirt, everyone wins! (almost)

If you wanna see my tits just ask...

 

[Eddo Rogue]

If you wanna see my tits just ask...

is that gonna cost me money?

 

[Dirtman]

Nope, just get in the basement.

 

[Eddo Rogue]

Hmmm tempting...would there happen to be any diodes down there?

 

[franklin2]

Your 12v that runs through the diode just feeds the relay coil. So there is hardly any load or power going through the diode, a 1.5 amp would be plenty big enough also.

 

[RonD]

Google: burbank, california electronic parts store

Tell them you want an automotive Diode, they should know, 1amp is fine, relays only draw 0.5amp

Under $1 unless you have to buy 10 at a time, then $5

DP-204 is the "package" you want, this means the shape of the diode, looks like this: https://en.wikipedia.org/wiki/DO-204


This is a different package and more often found in car fuse boxes: https://www.waytekwire.com/images/items/1Amp-Mini-Fuse-Diode-46880_f.png

These cost more, $8-$12, but might be easier to use with an "inline" fuse holder

Autoparts store will have this type and the holder