Test & Measurement
PSRR testing with analysers sans dc-bias ports
Here's a technique that involves the use of an analyser that has no dc-bias port but that can characterise frequency response as low as 10 or even 1Hz.
Single IC forms low-cost inductance tester
In this article, we show how to build a reliable, low-cost, and simple inductance tester. The basis for the tester is a Pierce buffered CMOS oscillator.
CPLD's internal oscillator does autocalibration
Read about an autocalibration sequence that synchronises a CPLD's internal oscillator with an external crystal oscillator, enabling ±0.3% accuracy.
Circuits guard outputs against over-voltage
Find out how to add a solid-state relay and control circuitry to an amplifier's output to provide over-voltage protection.
Low-cost way to measure motor speed
In this article, we present a microcontroller-based circuit that provides both an LCD readout and an analogue motor-speed output.
Mixed-signal-THD analyser for power-line distortion
To measure this distortion, you can use a mixed-signal-THD analyser to monitor the fundamental frequency amplitude and the second-, third-, fourth-, and fifth-harmonic content of the input signal.
Thermoelectric-cooler unipolar drive achieves stable temp
Peltier devices can both heat and cool, depending on the direction of current flow. This article shows an implementation of the concept in a high-performance PID-feedback loop.
Nulling out background illumination
In optical spectroscopy, a correct intensity measurement of the probe beam is crucial during material characterisation.