9 volt to 12 volt jump

I have a low amperage 9volt signal that i need boosted to a 12 volt signal. I have some standard relays but there isnt enough voltage/amperage to turn it on. Can I use a transistor to bump the voltage/ampreage up?

The real trick is that I cannot have this transistor turn on until the signal reaches 9 volts. When the signal is at rest, it sits at around 5.5 or 6 volts. C

Can this be done??

Please help me!

Are 9volt relays common? My local dealer only has 12 volt ones. I also looked in radioshack. Same result.

Mouser has them. Cheap too!

http://www.mouser.com/search/ProductDetail.aspx?R=FTR-P4CN009W1virtualkey52910000

Because of your at rest voltage I'd recommend a comparator circuit.. something like this..

http://home.cogeco.ca/~rpaisley4/Comparators.html

I'd think that a nine volt relay would maybe/maybe not trigger on 5-6 volts.

Jim

There is a circuit on this page that may help you out.

Lowest cost for 5V only supply with higher voltage relay coil

http://www.piclist.com/techref/io/relays.htm

You could play with the Resistor on this circuit to activate at 9v just put a Variable Resistor  instead of the resistor.

Put your 9v on the red arrow and tie the grounds together.

Here is the Modified Circuit.