# Power supply problem

#### Berzin

Joined Dec 17, 2020
59
Hi guys actually I have a circuit of 9 volts so how shall I connect to my 12 volt battery?
And if I keep full bridge diode rectifier to reduce the volts then will it work properly?

#### LesJones

Joined Jan 8, 2017
3,280
You need to give more detail. You seem to want to connect a 9 volt DC load to a 12 volt battery. Can you explain why you mention a bridge rectifier ? Also what current does the 9 volt load draw ?

Les.

#### Audioguru again

Joined Oct 21, 2019
3,316
What chemistry is the battery? A lead-acid car battery is usually 13.2V or more. A ten-cells Ni-MH battery is 14V when fully charged. A 3-cells lithium-Ion battery is 9.6V to 12.6V. A 9V voltage regulator has a minimum input voltage and a maximum output current.

#### MisterBill2

Joined Jan 23, 2018
9,022
Certainly the nature of the 9 volt load determines what is needed for getting the nine volts from the 12 volt system. And what is that 12 volt source? Some non-regulated 12 volt supplies that I have deliver about 17 volts at no load, but 12 volts when drawing the rated current of 300mA. so noth the nature of the load and the load current matter in this application. Without that all you get is guesses.