Troubles in My LED Dimmer Circuit

Flashlight Modding and DIY Parts
1

I have made a LED dimmer circuit which has 2 transistors,1 resistor and 2 potentionmeters. The brightness of the LEDs are dependent on the output voltage. Since the voltage regulator is variable, the brightness of the LEDs is also variable. The circuit is given below.

Comparing with the above circuit,the only difference is that I’ve substituted a few components & left out the 100r pot. I’m using an TIP122 ( TIP122 PDF )for the Darlington & a BD139 for the other transistor also a logic 1K pot. The circuit works fine but regards the pot it basically has no affect untill its turned half way round. Then there’s only a small bit of ajustment left between Off & On of the led.

I am wondering if there’s a way to make the pot work more evenlly. Or need I change the components?

Thanks~

2

Kynix Kitchenware.

3

On 2-nd of June you posted about a voltmeter with 741.., and then you dived in the darkness , without saying anything about...

Some people tried to help you then !... If the "Common Sense" is a notion not to familiar to you , I'll suggest you to google for it , maybe you'll understand...

Why should us care about your experiments, further ?...Think...

4

I know nothing about modding but remember that the Current is (near)0 below a min vf, then increases very quickly as the voltage is increased.
You may need to make the adjustment slower or use some kind of feedback like 7135 curcuits do.