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Topic: How to power 16 channel relay (Read 336 times) previous topic - next topic

scubieman

I want to buy a 16 channel relay. According to specs it says it needs 12v for the relay to energize. I noticed the arduino uno I am using has max output of 5v. How do I power this so the relays work?

Here is the link..... http://www.amazon.com/SainSmart-16-CH-16-Channel-Relay-Module/dp/B0057OC66U/ref=sr_1_1?ie=UTF8&qid=1403101563&sr=8-1&keywords=16+channel+relay

MarkT

That's not the datasheet...

It looks like it has 16 opto isolators so it takes 16 signals plus ground from the
microcontroller and a 12V supply (several amps probably) to power the relays.

http://www.sainsmart.com/arduino-compatibles-1/relay/16-channel-relay/16-channel-12v-relay-module-for-pic-arm-avr-dsp-arduino-msp430-ttl-logic.html
[ I won't respond to messages, use the forum please ]

johnwasser

Looking up the relay model number: "SRD-12VDC-SL-C" it turns out the the 'L' in 'SL' means the coil draws 0.36 W.  If that 'L' were a 'D' it would mean 0.45 W.

0.36 W at 12 V is 0.030 A (30 mA). 30 * 16 = 480 mA so your 12 V supply should provide at least 500 mA just for the relays.

The LEDs are powered by a 5V regulator running off the 12V supply so you probably need to add at least another 160 mA for those.

12 V 750 mA would probably be sufficient but  12 V 1 A would have more margin.
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jackrae

The unit signal inputs drive directly from the arduino 5 volt signals (your linked web blurb says so).  Power for the relays and onboard components comes from your external 12 volt supply unit.

scubieman

so where do I get the 12v from? If I power board using a 12v 1  amp power supply will that work?

johnwasser


so where do I get the 12v from? If I power board using a 12v 1  amp power supply will that work?


Yes.
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