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Support Forum » MOSFET, Light Bulb and NerdKits

July 30, 2009
by pedroh96
pedroh96's Avatar

Hey guys, I need some help with MOSFET and Light Bulb. I'd like to turn a bulb on using the MOSFET and the NerdKits. Look what I draw:

This is correct? Please help.

Regards, pH

July 30, 2009
by mrobbins
(NerdKits Staff)

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Hi pH,

If "power" means a 120V wall outlet, then the answer is no! Please don't try it! You will instantly fry your MOSFET (voltage and current limits, plus inability to tolerate reverse V_DS), and expose yourself to dangerous voltages.

Nothing is super-safe when you're working with 120V, but the "right" way to do it would be to use a relay, which is a device that has a control current passing through one set of terminals, which magnetically and mechanically switches another set of terminals open or closed. The relay coil could be driven much like a motor (as an inductive on-off load), but we'd need more details about the load and the relay.

Can you tell us more about what "power" means, and what kind of lightbulb?


July 30, 2009
by pedroh96
pedroh96's Avatar

Hey. It's a 50w. Light bulb and power is 110v. There's any way to do it just with the kit?

Regards, pH

July 30, 2009
by rajabalu21
rajabalu21's Avatar

I am afraid it is not possible to just use the NerdKit to get the job done. You may need a relay See link for example. You could use the MOSFET to drive the relay and then connect the lamp load to the relay's high voltage terminals. I strongly advice not to use the bread board for the relay contacts for the hight voltage side as safety might be compromised.

July 31, 2009
by Capt
Capt's Avatar

I would recomend not to make an project which include AC voltage as an main power for some device (light bulb).

First of, it's not 5 Volt DC. It's dangerouse, extremly dangerouse. From an outlet you could drain 16 amps(?^) the current needed to make your heart stop beating is just 30mA!

why not buy one or two led with high gain? Then you just need the mosfet and some resistors..

^ I don't know the amps ratings in 110. I've got 230.

July 31, 2009
by sgmaniac1255
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a typical household 120VAC Circuit runs on a 15 or 20 amp breaker, depending on the wires used to install it

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