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JeepHammer · April 10, 2016, 12:22 PM

I've been finding MOSFET switched timing modules and switches lately for dirt cheap...
Not that the average guy knows what this means, here is the rub...

Relays have mechanical contacts, no matter how low the current you run through them, the contacts opening and closing will eventually give up,
Or the mechanical parts, hinges, springs, ect. will fail...

MOSFET is solid state switching, no moving parts at all,
A fancy 'Transistor' that handles lower currents with these little units,
And I let the circuit board mounted MOSFET trigger a cheap, run of the mill relay, easy to find, easy to replace, about $1 in bulk when I need to switch higher currents...

The MOSFET trips the relay, the relay delivers the higher current to this or that...
It's an added step, but since the timers and other stuff is built into that little circuit board, the longer you can keep it living, the better off you are in the long run.
A bad higher power relay is easy to diagnose and replace, so it's a little more wiring in the front end, but it saves you a TON of aggravation over time!
These little surplus timer/switching circuit boards MIGHT NOT be so cheap and easily available when the unit decides to fail, so whatever you can do to keep them alive is a good idea...
At $3 to $7 each, it's not a bad idea to pick up your replacement parts now while they are cheap & available!

There is usually room in your DIY case for you to tape the extras in there somewhere, the bottom of my larger project boxes are always full of replacements, fuses, timers, relays, ect. since nothing fails until you NEED it, this puts me back up and running right away instead of trying to hunt down a replacement years down the road when you can't quite remember what the specifics where or where you got it from!

----------------

Something else you might want to consider,
When you are working with 12 or 24 volts DC,
It's perfectly acceptable to use AUTOMOTIVE FUSES, and other automotive components to work out your project...

Keeps the cost down, gives you an INSTANT source for relays, fuses, switches, ect., just as close as the nearest discount auto supply store!

April 10, 2016, 12:22 PM	#21
JeepHammer Junior member Join Date: February 27, 2015 Posts: 1,768	I've been finding MOSFET switched timing modules and switches lately for dirt cheap... Not that the average guy knows what this means, here is the rub... Relays have mechanical contacts, no matter how low the current you run through them, the contacts opening and closing will eventually give up, Or the mechanical parts, hinges, springs, ect. will fail... MOSFET is solid state switching, no moving parts at all, A fancy 'Transistor' that handles lower currents with these little units, And I let the circuit board mounted MOSFET trigger a cheap, run of the mill relay, easy to find, easy to replace, about $1 in bulk when I need to switch higher currents... The MOSFET trips the relay, the relay delivers the higher current to this or that... It's an added step, but since the timers and other stuff is built into that little circuit board, the longer you can keep it living, the better off you are in the long run. A bad higher power relay is easy to diagnose and replace, so it's a little more wiring in the front end, but it saves you a TON of aggravation over time! These little surplus timer/switching circuit boards MIGHT NOT be so cheap and easily available when the unit decides to fail, so whatever you can do to keep them alive is a good idea... At $3 to $7 each, it's not a bad idea to pick up your replacement parts now while they are cheap & available! There is usually room in your DIY case for you to tape the extras in there somewhere, the bottom of my larger project boxes are always full of replacements, fuses, timers, relays, ect. since nothing fails until you NEED it, this puts me back up and running right away instead of trying to hunt down a replacement years down the road when you can't quite remember what the specifics where or where you got it from! ---------------- Something else you might want to consider, When you are working with 12 or 24 volts DC, It's perfectly acceptable to use AUTOMOTIVE FUSES, and other automotive components to work out your project... Keeps the cost down, gives you an INSTANT source for relays, fuses, switches, ect., just as close as the nearest discount auto supply store!