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 ...
This circuit design for power supply on/off sequencing uses Schmidt triggers for triple-positive-rail timing purposes. Recent design ideas have explored the utility of timed power supply ON/OFF sequencing and provided circuit designs to implement ...
This page has two unusual two-transistor oscillators. I set the component values for a low frequency application. Both circuits draw only about 1 microamp of current. Materials on the topic Datasheet Fairchild 2N3904 Datasheet Fairchild 2N3906 ...
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 ...
Are you tired of dealing with the damaging effects of inrush currents on your industrial devices? Look no further than an AC inrush current limiter (soft starter). Inrush current, also known as surge current, is the large amount of current that ...
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 ...
A subtle change to a standard circuit can enhance its usefulness and even save a resistor. If there were a prize for the most trivial Design Idea (DI) of the year, this one would likely be high on the shortlist (if not at the top). Most DIs involve ...