Open collector output to operate relay

Thread Starter

capa_master

Joined Nov 26, 2010
4
Hi ALL,

I m having digital output with 150mA Max.Current and a Relay of "HLS-CMA3-B" rating:40A/14VDC 560W DC12V.

I need to operate this relay using this DIO(transistor's Open Collector Output).

Is this possible or any pull-up resistor is required if yes need detailed circuit.

Please reply ASAP.
Thanks
 
Last edited:

beenthere

Joined Apr 20, 2004
15,819
The spec on the relay gives the coil current. If you are able to supply the necessary voltage and current, then the coil should operate placed in series with the open collector of the transistor and the required voltage source. With the 12 volt coil, the current will be 150 ma.
 

SgtWookie

Joined Jul 17, 2007
22,230
You will need to use a diode across the relay coil to provide a path for current flow when the transistor turns off; otherwise you will blast the transistors' collector with high voltage.

I can't seem to locate a datasheet for a HLS-CMA3-B relay. Please check the part number, and locate a datasheet for it.
 

marshallf3

Joined Jul 26, 2010
2,358
It does need around 150 mA worst case @ 12V so you'll be fine if, as mentioned above, you place a snubbing diode across it. Any rectifier that's rated as fast, at least 200 PIV and good for an amp or two will work fine.
 

KMoffett

Joined Dec 19, 2007
2,918
+CTRL goes to your open collector output. GND goes to your logic common and the 12v power supply common. Connect a 1K pullup resistor between +CTRL and +12V, and you are good to go. :)
R2/D2 is just an indicator (not a robot from Star Wars ;) ), and not necessary.

Ken
 
Top