Pages: [1]   Go Down
Author Topic: Power supply for relay  (Read 270 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Full Member
***
Karma: 0
Posts: 146
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I have a project involving a relay, PIR sensor, and AC fan. All finally works as intended but it is so ugly, really ugly, with two wall warts, one supplying the Arduino, another for the relay, and a wire for the fan, all coming from a power strip. A single wire from the AC outlet to a box would be much more elegant.  I assume the Arduino and relay can't be supplied by a single wart via transistor, or in this case, a tip120?  Could mains power be accessed from a single terminal inside a project box by the two warts? Ignorant question, but anything coming from the wall gives me the Willies!
Logged

Massachusetts, USA
Offline Offline
Tesla Member
***
Karma: 179
Posts: 8081
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

You have not said what voltages and currents you are using.

I can guess that your relay requires more than 5 V and/or more than 30 mA.  Perhaps you should look for a different relay.

If your relay used 5V and <30 mA you can run it directly from an Arduino pin without a separate power supply or transistor driver.  If it uses 5V and >30 mA (up to about 400 mA) you can drive it from the Arduino with a transistor.
Logged

Send Bitcoin tips to: 1L3CTDoTgrXNA5WyF77uWqt4gUdye9mezN
Send Litecoin tips to : LVtpaq6JgJAZwvnVq3ftVeHafWkcpmuR1e

Offline Offline
Full Member
***
Karma: 0
Posts: 146
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Thanks for the help. The datasheet says 40ma. Having ordered a bunch of these, guess I will try to use them. If run from a transistor, I assume two wall warts are necessary?
Logged

Massachusetts, USA
Offline Offline
Tesla Member
***
Karma: 179
Posts: 8081
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

You have still not said what voltages you are using for the relay or Arduino.
Logged

Send Bitcoin tips to: 1L3CTDoTgrXNA5WyF77uWqt4gUdye9mezN
Send Litecoin tips to : LVtpaq6JgJAZwvnVq3ftVeHafWkcpmuR1e

Offline Offline
Full Member
***
Karma: 0
Posts: 146
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Sorry, I am using 6v for the Arduino Pro, and 5v for the 5v relay.
Logged

Pages: [1]   Go Up
Jump to: