A voltage divider is probably the most common electronic circuit. Despite its simplicity, it can be a design challenge for many folks, particularly beginners. This article presents a fast and accurate way to design a variable voltage divider with minimum math.
A voltage reference is a zener diode-like semiconductor that produces an accurate fixed voltage; often, five or 10 volts. The downside to a voltage reference is that it only generates a single voltage and has limited current output. I decided to design a circuit that could generate any voltage between zero volts and 10 volts in 0.1 volt increments. Here’s how I constructed my variable voltage regulator.
Most frequency counters can tolerate only low levels of RF at their input, but here’s a way to safely measure the frequency of an RF signal of up to 200 watts with your existing frequency counter.
Over the years with different companies I’ve worked for, I always had access to high-end audio THD (Total Harmonic Distortion) analyzers. I found these very useful for design work, debugging, and repair of audio equipment. My present company has no need for them and consequently they aren’t included in their armory of test equipment. Oftentimes, I have need for one but could never afford to own one — not even a used one. I thought this would be a worthwhile project, so this article describes how to construct one.
Sometimes I wonder which of my portable digital voltmeters I can trust — the B&K, Fluke, or Amprobe. Usually, they’re pretty close but it bugs me not knowing whether they are right on the nose. Fortunately, these days, there are a number of very accurate voltage reference circuits that you can build or purchase for a few dollars.
During a recent vacation, I challenged myself to come up with a design for a continuity tester that suits my particular testing requirements. Most of the time, I go straight for a microcontroller, but this time I decided to use only non-programmable components. I also decided to use only through hole components, to make soldering easier.
In decades past, capacitor and resistor substitution boxes were very popular pieces of test equipment. These days, it seems folks have forgotten their value and ease of use. Here’s a discussion on how they work and the different options and styles available, so you can start using them for yourself.