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Thank you for all your help, I really appreciate it. Both 35V/10uF and 50V/22uF caps are the same size. Now I just need to wait for the module from dx, it has been 70 days since it was shipped.

I've done another driver for the third time, now with ¼W resistors and everything bent and trimmed to fit in a 14mm cylinder with less than 20mm of height, but I used a 50V 22uF capacitor. Does that mean a capacitor with a larger value can result in a voltage rise? Here is the third driver I...

I think both resistor from that picture are 1W and the Rsense is 2.7 ohm. It was just for testing, I've built another driver with a 1W 2.2ohm Rsense and a ¼W 1K, it outputs 270~280mA. The caps I used on both driver are 35V 10uF but I also have some 50V 22uF caps of the same size, would it make a...

Once again, sorry for asking so many questions, but, what is the power dissipation over the 1K and Rsense (2.2ohm in this case) from a 4.2V input?

The wrapping on the 4 Sanyo cells I'm selling are intact, I only damaged the wrapping on the other 2 cells that I will keep for myself. But the wrapping on the blue cells were torn apart from extracting them, still usable, but ugly.

These cells can discharge to 2.75V, and I didn't know Sanyo 2600mAh were $12 a pair. I'll drop the price of 4 cells to $15 shipped to Europe and $20 to the rest of the world. I don't have equipment to accurately measure the cells' capacity, so I'm selling the them as-is. The unidentified cells...

I have 6 Sanyo UR18650A from a laptop for sale. I damaged the wrapping on 2 of them which I will keep for myself, the other 4 cells are okay, I only removed the tabs from them. They were all between 2.8~3.1V when I pulled them from the battery, then charged them to 4.20V with my LM2596 DC-DC...

It was just for testing, I need to trim all that to fit in a 14500 host somehow. BD140 gets hot very quickly, should I heatsink it? It's going to power an LPC-826 at 250mA from a single 14500. I'm trying not to mess up on my first build.

I was able to get a BD140 locally today and built the driver, with a 2.7 ohm Rsense and a 10 ohm resistor as a dummy load it outputs 0.25A with any input voltage above ~3.3V, tested with a variable dc converter. http://img837.imageshack.us/img837/7859/20121113173927.jpg

Will two BC557 be enough for about 200mA? Input 3~4.2V, output 2.8~3V. I only have BC557s and BD139s.

Can I use a BD139 instead of the BD140?

Bump?

Or case negative version?

I already of all the parts I need for this build, the diode is still on its way here. I've drawn a schematic of my build, green lines are ground and red lines are positive, the host takes 12mm module without the need for a heatsink, black circle is a switch, purple rectangle is a high-side...

But could it be used to safely charge a lithium battery from usb, even if CC only? What charging voltage would it reach this way? I already bought a 5- and 10-pack of these transistors for a case negative build, and I wanted to integrate a small lithium charger inside the host.

Can this 2-pnp driver also be used to charge lithium batteries from usb?

Sorry, should've mentioned that. What current should I use for continuous operation?

Hi, I have a very simple question, what is the max current I can supply to an LPC-826/836 heatsinked only by an Aixiz module? The "Aixiz" is actually this red module from DX, it will go inside an old AA green pointer's host.

Thank you to whoever edited my diagram, I only saw this right now.

Thank you all for your help, but is there any high-side switching/sensing buck I could use for an lpc-826?