Hi. I am a Product Designer currently working on a project involving some LED lamps. I am trying to mock up a couple of prototypes to try some ideas with, rough and ready card mounted things. What I need is two banks of about 3 LED's ideally controlled by one potentiometer and switch but with two batteries.

I've mocked up a couple of circuits in crocodile clips, one of my own making and one from this thread: LINK

The circuit from this site works perfectly and has lots of control on the brightness of the LED's. My circuit however which has the 12v split between two 6v batteries is giving me very little control.

Can anyone suggest any ideas for increasing the amount of control from the potentiometer and also for maybe reducing the voltage say 4.5v per battery 9v total

 

Hi Calmrott,
you can try using a higher resistance for the potentiometer & check the circuit. possibly the potential drop caused by the 1KΩ may be too less.