### Coulomb, mA and mAh

I am sure I will forget all this later, so...

A Coulomb (C) is defined as 1A * 1sec. This implies 1A = 1C/sec.

In the previous example, we have a 4V/2600mAh battery driving a 1K resistor. Through the LTC4150, we are measuring consumption of 0.614439C in 150.8s,

Load = 0.614439C / 150.8s = 0.004075C/s = 4.075mA
Therefore battery should last 2600mAh/4.075mA = 638 hours

What if you have varying loads? eg.

(1) Load = 0.614439C for 180s = 0.00341C/s = 3.41mA for 3 mins
(2) Load = 0.614439C for 60s = 0.01024C/s = 10.24mA for 1 min
(Repeat)

Average load = 2 * 0.614439C for 240s = 0.00512C/s = 5.12mA
Therefore battery should last 2600mAh / 5.12mA = 507.8 hours

### Adding "Stereo Mixer" to Windows 7 with Conexant sound card

This procedure worked for my laptop (Thinkpad E530) with a Conexant 20671 sound card, but I suspect it will work for other sound cards in the Conexant family. I was playing with CamStudio to do a video capture of a Flash-based cartoon so that I can put it on the WDTV media player and play it on the big screen in the living room for my kids. The video capture worked brilliantly, but to do a sound capture, I needed to do some hacking. Apparently, there was this recording device called "Stereo Mixer" that was pretty standard in the Windows XP days. This allowed you to capture whatever was played to the speaker in all its digital glory. Then under pressure from various organizations on the dark side of the force, Microsoft and soundcard makers starting disabling this wonderful feature from Windows Vista onwards. So after much Googling around, I found out that for most sound cards, the hardware feature is still there, just not enabled on the software side. Unfortunately, to

### Hacking a USB-C to slim tip adapter cable to charge the Thinkpad T450s

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