I am trying to connect a non-inverting amplifier (op-amp 741) output to a relay. The amplifier gives me the output that I need which is about 7V. However, the moment I connect this to the relay input, the voltage drops to about 2V and thus the relay does not switch. I'm using a electromechanical relay which is normally open(6V relay). Why is this happening?

Is a 2V relay available in the market?If yes, please let me know where.

Thank you.

 

this is normal... 741 is not designed to provide big output current.
it was designed to have big gain. nowdays, thins are a bit different
so there are OpAmps that can handle much more current.
another thing is that realys are not normally driven by OpAmp.
You need digital (on/off type) signal to operate relay properly.
If the 741 output is working like that in your application, all you need
is a transistor to get the current big enough to turn on relay.
if you need more help, try posting your circuit.

 

Thank you for your quick reply.

I'm a little unsure about whether a relay is turned on by voltage or current or both voltage and current?

Do you mean I have to use a transistor to amplify the output current from the 741 op-amp?

What models of op-amp will provide me a larger current?

Thank you.

 

panic mode wrote
i agree with this ,the tran should be good enough
you can use simply AC 187 and no need to change op-amp

 

A relay's specifications will include the coil's resistance and the nominal operating voltage, or small range of voltages.

It is the current through the coil's winding ( caused by applying the voltage across it ) which produces the magnetic field necessary for the relay's operation.

 

The mention of using an AC187 transistor brings back fond memories.
It's an old germanium transistor in a cylindrical metal case!
It doesn't even need base current to turn on, just warm it a bit.
You want to know what "thermal runaway" is? Ask an AC187, its the expert.