Soldering practice and a power supply project update

The results of my practice run tonight.

Tonight I took advantage of the milder temperatures and soldered a few SMT resistors onto a scrap PCB as practice. It went smoothly, with the exception of Q1, which hopped when I applied too much pressure while tacking it down. While it looks a bit goopy, it tests out alright. Still a bit too much solder on some of the Rs. Unfortunately I do not have any magnification other than my camera lens, so it’s hard to inspect my solder work in any  great detail. Clicking on the photo above does offer a bit of zoom, however. Particularly pleased with R1. A definite improvement over my first attempts. Looking forward to more practice with finer pitch IC packages.

Power Supply Update

Basic power supply circuit from Dave Jones’ EEVBlog (Screen capture from Video #3)

After watching Dave Jones’ 5-part lab power supply series, I’m beginning to grasp some analog circuit basics and am eager to try breadboarding my own constant current/voltage supply circuit. To help me design my own power supply unit, I’ve ordered IC samples, capacitors suitable for decoupling/noise reduction on the supply line and op amp bridges, and resistors with a suitable tolerance for the voltage shunt/current sense amp. I was able to scavenge two sturdy potentiometers from some old electronics to feed the op amps in setting the voltage and current levels. Other components, such as the 12-bit DAC, will allow a micro signal the op amps and adjust the current and voltage at a decent resolution (0 to 4096). Jones’ schematic shows two single-turn potentiometers accomplishing the same task.

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Filed under DIY, Lab bench, micro-controllers, Soldering

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