From: Benny B. S. <bb...@se...> - 2009-10-11 09:59:43
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Omit the optocoupler (the relay should be chosen so that it has sufficient isolation voltage between coil and contacts). Connect a GPIO to a driver (e.g. a MOSFET or ULNxxxx) that is able to drive tho coil on the relay (and remember flyback diode on the coil if the driver can't cope with the voltage spike from the coil when switching off) The relay is the simple solution. A single MOSFET won't go on the ac side (a MOSFET has a diode from source to drain) BR Benny bahnfire skrev: > I would connect a GPIO to an optocoupler and then a relay. If you have >5 > outputs then use a ULN2803. If the load is inductive make sure you use a > flyback diode across the load terminals. I used a PCJ-105D3MH SPST-NO relay > before for a 1-2A load and it was fine (contact rated to 5A @ 240VAC) and it > has a 5VDC coil (needs 40mA, so you will need a mosfet or transistor to > switch). > > Cheers, > Paul > > > hypo wrote: > >> hi experts, >> >> I want to control power to my living room lamp (runs on 110V AC mains) >> with a verdex xlp. has someone tried something like this before? if so, >> i'd appreciate any tips and suggestions. >> >> here's what i'm thinking of doing: >> 1. connect one of the GPIO ports to an opto-coupler >> 2. connect the isolated output of the opto-coupler to driver circuit >> 3. the driver circuit drives the gate of a power MOSFET that controls the >> lamp. >> >> is this feasible? if so, does anyone have suggestions on any specific >> parts i could use? esp for the opto-coupler and power MOSFETs? i'm think >> it has to be able to handle 110V and ~ 2A for continuous operation for at >> least a few hours at a time. >> >> is there a better (= easier, cheaper and safer) approach to doing the same >> thing? if so, what hardware would i need for that? >> >> any guidance on any related topic is more than welcome! >> >> thanks a ton! >> hypo >> >> > > |