Is this for a lawn sprinkler, etc .. ?

Would the Timer motor be powered by 12v (DC) ?
or from the 120v wall outlet ?

There are some 120v wall timers ...
electronic (programable) ON or OFF at dusk for about $ 25 ...

need to program which mode you want ..
ON at dusk OFF at dawn
ON at dusk and OFF a certain number of hours later
OFF at dusk ON at dawn
OFF at dusk and ON a certain number of hours later

etc...

Oops. I failed to note it is a 12volt 2amp DC circuit.

It is located out in the desert so whatever turns the circuit on and off must be a solar normally closed switch or a battery.

OK, we're getting closer ...

possibly you have a solar panel w/battery ...

and you want to turn an external circuit ON during the day ?

or to just disconnect the solar panel from the battery at night ?

If you tell us what it is that you are trying to control you get a better answer.

I use such a circuit for controlling an alarm system on a disconnected tool shed using Solar Cells. You can use any type of a relay to power or remove power from any circuit depending on the current capabilities of the relay. BTW, I built my circuit from schematics I got Online. It basically is a light sensor feeding a transitor switch to turn ON or OFF a relay. It has an adjustment control to set the threshold bias on the transistor for the crossover point of light and dark. Has been working for over 10 years with the Solar Cells charging batteries that feed the circuits for the alarm system.

"keyword search problem"

THAT MUST BE IT.

No, "it's a I don't know how to do this , can you help me" probelm.

Not the "I can't or won't ask the question problem, because I can Google anything I need"

We'll help, just ask.

KEN