SparkFun Forums

[pauld]

HI! Its been a long time since I dabbled in electronics so plz bare with me

I am wondering how to actually power my 12v DC Dosing pump ( Current:80mA ) with a controller which according to its specs has a 5V relay ( note from supplier below ).

1: So I need a 12v relay/switch that gets activated by a 5v right? as from what the controller says below is that is open or closes a 5v circuit or am I misunderstanding this?




--------Note from supplier ---------------

Minimum and maximum control points will activate relay controls via switching dry contacts.

Relay Control: The unit will transmit an analog signal (simple switch) via open or closed contacts to a device (e.g. pump/valve) when the ppm/µS level reaches the maximum TDS/EC limit (Control Point 2) or the minimum TDS/EC limit (Control Point 1). The contacts are switched back to the normal position once the TDS returns to the acceptable range.

Relay Voltage: 5V (attached devices must have their own power supply)

[paulvha]

The coil of the relay needs 5V to generate enough magnetic power to change the position of a lever to which the contact points of the switch is attached. The coil connection needs 5V and you will need to have a separate 12V supply connected to the switch and the pump.