.:madworm:.'s photos

Why does the boot-screen duration depend on the time-base setting?

It is surprisingly hard to find those semi-insulated binding pots. Most of the available ones are fully insulated.

These heatsinks are quite affordable, thanks to mass production.

Each of those is worth 6 scoops of ice at one of the Italian Ice Cafés in town. If the scoops are big or hilariously small depends on location. The red caps are 38¢ each. The fit is surprisingly loose. I would have liked them to stick firmly and not pop off easily.

Too bad I already knew what was in there.

Princess Barferella's new car. What colour is this? I wouldn't buy ANYTHING with that colour - not even drunk. Not that I drink much...

This version provides basic capability for microcontroller remote control using 0-5V signals. It takes 0-5V as a set-current intput and spits out 0-5V signals for the DUT voltage and current (both clamped to 5V using Zener diodes). I did NOT include an RC low-pass filter for the input. Either use a micro with a DAC or add a simple filter elsewhere. After completing a device for my own 'happy happy joy joy', I will be having a few boards left over - as usual. This time it will be 4 boards. If it works as expected, the remaining 5 boards will go into another DIY-kit experiment. These will be available via my blog - if you want it or not ;-) Schematic and all design files .

I don't really remember why I added the big pads when I did the layout, but I has proven to be good.

Not ideal (free-standing TO-220), but tolerable for a bug-fix. The diode's characteristics are quite good. Datasheet

Not ideal (free-standing TO-220), but tolerable for a bug-fix. The diode's characteristics are quite good.

WingShing 78L05. 'Normal' 78L05 are supposed to survive an input voltage of 30V. These however get seriously sick at around about 27V. And instead of shutting off the output, the output voltage rises considerably. I measured 7-8V. So I've marked the bag of 100 (ebay) with 25V max. I can live with that, but they should at least have added a datasheet / specsheet. WS78L05 datasheet . Hmmm. Absolute maximum: 30V (WRONG). Recommended: 7-20V ... oh well...

I added a 3V battery to pull the p-ch gate to -3V. It improves the R(ds)-on at small positive input voltages, but completely defeats the reverse polarity protection. ARGH. I do have to add a Schottky diode at last.

Desoldering a TO-220. I removed most of the solder with braid and wiggled the thing out. BUT I managed to pull out the through hole plating on one hole. Fortuitously the pad didn't lift. That would have "made my day". I got the forceps at a local pharmacy. It was about 4€ - and I didn't have to pay anything for shipping. It works quite well as a heatsink, but it is a bit too large for small diameter stranded wire. According to wikipedia, this type of forceps causes only 'minimal' trauma to tissue - at least compared to other clamping devices used by surgeons. HOWEVER, when testing this thing on a piece of skin that is readily available (between thumb and index finger)... OUCH!

I was thinking I had serious problems with the control loop on this thing. And it turned out to be my PC's power supply radiating CRAP. As soon as it is off there is perfect silence. That is the downside of using a low-Ohm shunt resistor and additional amplification. Note to self: only use RF-tight project boxes ;-)

When all runs fine, the current noise is pretty low. However it doesn't like transients... but it is not made for that.

Sometimes there is some HF oscillation going on. I don't know if it is the DUT or the dummy load. It goes away pretty quickly.

Pulling 5A out of a 5V switch mode power supply. Voltage has dropped a bit, as this device is only rated for 3A.