Archive for May 2013

Cheap DMM Calibration With Precision Voltage Reference

Having a decent digital multimeters is an absolute necessity if you are doing any types of electronics work (see Dave’s DMM Buying Guide). Those cheap sub-$10 multimeters are usually too inaccurate to be trust-worthy for any kind of serious measurements. That said, because of their affordability they remain quite popular. I usually would bring one of these when doing casual work in the field so I do not have to worry about losing it or damaging it. Continue reading ‘Cheap DMM Calibration With Precision Voltage Reference’ »

Avalanche Pulse Generator Build Using 2N3904

Avalanche transistors can be used to generate fast rise time pulses. Their usage in the hobby world was made popular following an application note (AN72) by Jim Williams and was further publicized via this EEVBlog video. Many people have built such avalanche pulse generators for oscilloscope bandwidth measurements. In this post, I will show you the one I built using a general purpose BJT as well as some rise time measurements. Continue reading ‘Avalanche Pulse Generator Build Using 2N3904’ »

QFN Soldering Using SchmartBoard

I wrote a tutorial a while ago on how to hand solder fine pitched LGA/QFN chips using perfboards. While The technique illustrated works well with low pin count chips, for many people it is still a rather daunting task to solder these tiny chips that way. Also, as the pin count increases hand soldering without using a board with proper footprint becomes much harder. Continue reading ‘QFN Soldering Using SchmartBoard’ »

Westinghouse L2410NM LCD Power Supply Repair

My seven year old 24 inch LCD monitor (Westinghouse L2410NM) started to flicker recently, so I decided to take a look inside to see what was wrong. Even before I opened it up, I had a pretty good idea of what might be the culprit. These older LCDs use CCFLs for back-lighting. CCFLs are typically quite robust. While it is not totally impossible, it is rather rare to see a failed CCFL. So most likely the issue is related to the power supply module. Continue reading ‘Westinghouse L2410NM LCD Power Supply Repair’ »