Posts tagged ‘Analogue’

The power bank in use: a small rectangular grey box is shown on top of a lead gel battery with a USB cable connected to one of the sockets on its left side. On its top right side, a small grey power switch and a green power indicator LED are poking through the case. The module is connected via the 6.3 mm contacts, which also holds it in place on top of the battery.

The grey box with the top lid of the case removed, revealing a PCB with the USB A sockets, power switch, LED and a few electrolytic capacitors on top. At the front of the picture, the battery contacts (soldered to the bottom of the PCB) and their holes in the case can be seen.

Pb Power bank

In preparation for being off-grid for a few days, I quickly built this ‘power bank’ around a 12 V 7 Ah lead gel battery. The circuit is simply pushed onto the battery’s 6.3 mm contacts and provides 3 USB ports. Charging circuitry is not included but the battery terminals are still accessible anyway.

Quick and Dirty B–H Plots

While building solenoids, I needed a way to quickly judge the magnetic properties of some unknown steel. A simple analogue hall sensor IC works together with a controlled current source for the coil to drive a XY plotter (or oscilloscope in XY mode) and create simple B–H plots.

Philips PM 3265 Repair

This post was the first post of my first attempt at a blog (which was never published). Albeit I since re-wrote it completely, I decided to keep its original date, which consequently now predates the date this site went online. I still like analogue scopes. Although the convenience of a digital scope’s features is hard to be matched, I still like to come back to the older world from time to time. Read more →

IGBT Chopper

A useful thing to have for testing high voltage transformers is a simple chopper. This one switches a 600 V IGBT with an adjustable frequency between 50 Hz and 29 kHz (lower frequencies are possible with an external timing capacitor) and any duty cycle between 0 and 100%.