Pulse Width Modulated LED Torch

Step 8 Finished Torch

Transferring the circuit to veroboard is challenging, especially condensing the relaxation oscillator so it will fit into the case. The main thing to check is that no wires are crossed, or are loose enough to cross. Adding another 5 LEDs, a switch in series with a battery connector and then placing these into a case is more straight-forward.

Connecting the power supply to the battery connector to test the circuit, the average current reading was approximately 85mA. This is significantly smaller than 180mA (6*30mA) that a direct drive system would require.

I have not gone into great detail with transferring the circuit from the breadboard, onto veroboard as I have aimed to concentrate on the theory behind this project, rather than specifically it's production. However as a general guide, you should test the circuit and get it to work on the breadboard, then transfer the components to the veroboard, starting with the smaller components. If you are competent and quick at soldering, you may be able to safely solder a chip directly to board, otherwise you should use a chip holder.

Comments

[luckyvictor]

 so your LED are connected in parallel??

[mathews]

Yes, each with its own current limiting resistor.

[recuat]

in step 2 there is a i.c. or transistor in the picture? no part no. please reply. thanks

[mathews]

No, there is not.

You can select an NPN transistor based on the current required for the LEDs you are going to use. This selection is a design decision you must make, and I cannot make for you.

[luckyvictor]

 Thank you very much for replying me, as you can see from my detail, I am a newbie to electronics and just join recently, I have a question about powering up 12  LED, would you mind to have a look of the following link and give me some technological advise please?

http://www.instructables.com/answers/Power-for-12-LED/

thanks again for your time and advise