GPIB Interface for PM3365A Oscilloscope

2017-11-05 by rincewind

The Philips PM3365A oscilloscope I inherited last year works fine – but it has one drawback: the only way to export data is via a GPIB interface. I had the opportunity to borrow a Prologix GPIB interface to test what can be done with this interface – it turns out remote control of the oscilloscope[…] Read More…

Medium-Speed Isolated Power Switch

2017-09-17 by rincewind

The isolated power switch presented here was built to do repeated power-up/power-down tests on a power supply. I basically needed a MOSFET that could be controlled by a PC. To keep the circuit universal, the following design goals were added: Isolation of the switched circuit from the PC, so the switch can be used in[…] Read More…

RSA306 repair

2017-08-23 by rincewind

Fixing the broken USB connector on a RSA306

Low-Power Joule Thief Night Light

2017-02-19 by rincewind

The classic Joule-Thief circuit can be modified to work in a low-power burst mode: The base resistor R4 is increased to a value that provides just enough base current for startup. After startup, the base current is provided by C1 and transformer L1-L2. Each cycle, the B-E diode of Q1 charges C1 a bit, until[…] Read More…

Keithley 129 Display Repair

2016-12-27 by rincewind

The LCD on my Keithley 129 multimeter (which was the first big investment into my electronics hobby ~1982) has turned black over the years. The original LCD is a custom type with zebra-rubber contacts on one side, for which I could not find a source: The standard 3.5 digit displays are too big to fit[…] Read More…