Category: Electronic


18650 battery tank (mobile battery)

There are battery tanks (mobile battery) in different sizes and styles. Equipped with (at least) a lithium ion cell (E.g. 18650) they deliver 5V at output (for.5A). A charging circuit are integrated (CV/CC procedure), a Step-Up Converter as well as a protection circuit against deep discharge. The latter is...


Upper surface roughness of a 250 GB platters

It scans a 250 GB platter with the laser scanner, the following picture emerges. The "Roughness" or amplitude is in the range -0 1µm. However, has dust according to definition a particle size of 2.5 10 µm, thus 25-100 is greater. This is one reason, among others...


Transistor Tester/component testers the polymath

Conceived and designed by Markus Frejek, every hobbyist knows well this problem: one expands a transistor out of a unit or extracting a Pocket from the Junk box. If the designation is to identify (and one is known), everything is...