A single cell Li-ion charger

Here is a single cell Li-ion charger that was rigged up during Christmas break. It's working well so far and am using it to charge a 5.4Ah(4 cells in parallel) bank. I know that charge rate is low but my adapter can hardly sustain the 650ma of current.

Happy new year to all U folks.

white LED drive from 12V -- 2

Here is another of my 12V LED projects.

This circuit is useful to while driving a large number of white LEDs at 12V as it reduces part count.

I am posting this as an original circuit as I could not find a similar one on the net till date.

I am using 3X10 White LEDs on this circuit and have found performance to be reliable -- no string dead so far yet and brightness OK too.

white LED drive from 12V

12 volt battery has been a fixation for me. TRYING TO GO GREEN AND THE CURRENT 12 V LEAD ACID BATTERY STANDARD 

Currently, 12v lead acid battery is the most economical source of stored energy and so, trying to make the most out of it, I try to design - redesign on that voltage.

Here is an old redesigned white LED drive which I have replicated many times and may be of use to some of you. Current dropping resistors are not reliable in the long run and after wasting many a LEDs I have found this circuit works well. BTW the design is specific for lead acid battery -- its useful voltage of  12.7 to 10 volts

3 white LED in a string is just right for a 12v battery and linear regulation is efficient enough for such an application. Current through the LED is best kept below 20ma and is controlled by the 33 ohm resistor. Trial and error is applicable in setting this resistor but 33 ohms 10%  is a good value as it is found to keep the value between 15 - 20 ma .

The circuit works well 10+ volts. I have been using multiple strings of the same circuit for 2 yrs without failure till date.

Thanks to the people who posted the PNP version that I first saw

First Post

This is my first post on this blog being created and also my first try on blogging.


This blog is being created to give back a bit to all netizens from whom I have taken and gained a lot. Thanks to all of you.

Will try to focus on simple electronics, which is my main hobby.

I do hope to get the first useful post out soon,