Archive for April 2013

Tektronix 2445 Teardown

I bought an old Tektronix 2445 150 Mhz oscilloscope on eBay the other day. It was listed under “For Parts/Not Working” condition. Since the pictures in the auction listing suggested that the scope powers up and shows traces on all channels, I thought I would get it and fix it up. Continue reading ‘Tektronix 2445 Teardown’ »

Building a Sweep Generator for BK 4011

I did a teardown of a BK Precision 4011 5MHz function generator a few weeks ago. Like most of basic function generators in old days, BK 4011 does not offer frequency sweep as an option. What it does include is a VCG (Voltage controlled Generator) input, which essentially is just a VCO and it can be used in conjunction with an external sweep generator to generate frequency sweeps. Continue reading ‘Building a Sweep Generator for BK 4011’ »

A Bidirectional Level-Shifting Buffer for Raspberry Pi

The current sourcing/sinking capability of the I/O pins on Raspberry Pi is quite limited. According to the Wiki page, the current limit for each I/O block (e.g. GPIO0 through GPIO27 combined) comes at only 26 mA maximum, which is only capable of driving a couple of LEDs at a time. Also the I/O pins are 3.3V only, and going beyond the current or voltage limit could result in permanently damages to the chip. Continue reading ‘A Bidirectional Level-Shifting Buffer for Raspberry Pi’ »

BK 4011 Function Generator Teardown

I got a used BK Precision 4011 5MHz function generator recently. The 4011 model is rather old and this particular unit was manufactured back in 1996. But BK precision still makes a similar model (4011A) which is identical to the older 4011 spec-wise except for the inclusion of an additional INV button for inverting the output waveform. Continue reading ‘BK 4011 Function Generator Teardown’ »