Circuits & Schematics - Measurement

Simple circuit ratios sensor capacitance to reference capacitor to measure micrometers. It’s hard to imagine a simpler electromechanical sensor than the capacitance type, consisting of little more than two plates (or even just one if the ...

Simple to build, but serious instrument for monitoring and predicting weather disasters Lightning detectors are devices designed to detect the presence of lightning strikes. These detectors utilize various technologies to sense the electromagnetic ...

Ground-referenced loads are common in industry. This circuit implements current loop conversions for them. Recently, there have been several published Design Ideas on converting 0/20 mA to 4/20 mA current and 4/20 mA to 0/20 mA current as ...

It’s always gratifying when a simple and successful design idea luckily turns out to have additional applications that you didn’t originally envision. Here’s an example. A while back, the design shown in Figure 1 was accepted for ...

Ordinary bipolar junction transistors can sometimes be precision sensors. When you think of precision components, you usually don’t (and probably shouldn’t) think of general-purpose bipolar junction transistors. Are GP BJTs cheap and ...

The circuit is powered for years by a single 3 volt lithium battery. It sounds an alarm when the temperature exceeds a certain point. With some minor changes the circuit could also be configured for an under temperature (freeze) alarm. The circuit ...

Op amps tend to make analog design easy. Maybe sometimes too easy? Don’t get me wrong. I like operational amplifiers. Some of my best friends are op amps. They embrace such a wide range of varied capabilities, including low noise, high power, ...

Combining an accurate temperature sensor with a standard digital multimeter can make an inexpensive, accurate, and useful thermometer. A recent Design Idea, BJT is accurate sensor for absolute temperature in Kelvin and Rankine ( Ref. 1 ), was based ...

Simple math implemented in a (very) simple circuit. What’s not to like? A very cool (also warm!) property of the base-emitter junction of (most) small signal BJTs is the ΔV BE temperature-sensing effect. ΔV BE temperature ...

Circuits such as the design described here implement useful tools for a diversity of calibration and testing applications A two-wire loop current generator is a useful tool for the testing, calibration and commissioning of current-to-pressure (I/P) ...