stepping up from o.1 volt dc to 9volts dc?

[granada1]

Hi, I am trying to increase dc voltage from 0.1 volt to 9 volts, together with enough milliamps to be able to power a spst reed relay. any ideas gratefully received.

thanks

 

[MikeMl]

Do you mean that you want to amplify a 0.1V change to cause it to pull in a small relay using an external source of power?

 

[granada1]

Hi MikeM1

yes, I am trying to amplify 0.1volts to 9 volts using an external dc supply, to trigger a small relay. thanks

 

[MikeMl]

What is the ground-reference for the 0.1V signal?

Two Darlington-connected NPNs; An OPamp amplifier with a gain of 100 controlling the base of an NPN or gate of an NFet; Use a DC supply which matches your relay. 9V relays are hard to find.

 

[granada1]

Many thanks Mike ML for sorting this.