Circuits & Schematics - Analogue Design

High accuracy, stability, and wide operating range make platinum RTDs (resistance temperature detectors) popular temperature transducers. Signal conditioning these devices requires care to utilize their desirable characteristics. Figure 1’s ...

Accurate, inexpensive, and mature platinum resistance temperature detectors (PRTDs) with an operating range extending from the cryogenic to the incendiary are a gold (no! platinum! ) standard for temperature measurement. Similarly, the 4 to 20 mA ...

The classical Schmitt trigger circuit that you'll find in textbooks provides some noise immunity, such as for the front end of magnetic pickup in position-sensor circuits (Figure 1a). You adjust the two threshold levels using R 1 and R 2 or R 2 ...

Precision-matched resistors, diode pairs, and bridges are generic items. But sometimes an extra critical application with extra tight tolerances (or an extra tight budget) can dictate a little (or a lot) of DIY. Figure 1’s matchmaker circuit ...

A simple circuit can improve the dynamic performance of a phototransistor for use in low- to medium-speed applications as fast as 100 kbps, such as optical isolation of an RS-232C serial line (Figure 1). In low-cost applications that require high ...

There are multiple means of generating analog sawtooth waveforms. Here’s a method that employs a single supply voltage rail and is not finnicky about passive component values. Figure 1 shows a pair of circuits that use a single 3.3-V supply ...

Analog designers often need matched resistors for their circuits [ 1 ]. The best solution is to buy integrated resistor networks [ 2 ], but what can you do if the parts vendors do not offer the desired values or matching grade? The circuit in ...

Recently (5/21/25), I published a Design Idea (DI) describing a bidirectional current mirror using just two transistors and a diode, “A two-way mirror current mirror that is” ( Ref. 1 ). That circuit works well in some applications, ...

In the first part ( Ref. 1 ) of this Design Idea (DI), we saw how to use the TDA7052A (or similar) power amp to build a minimalist siren-type power oscillator, and also, having looked at that device’s distortion characteristics under various ...

When audio power amplifiers oscillate, the result is often smoke, perhaps with a well-cooked PCB and a side order of fried tweeter. This two-part Design Idea (DI) shows some interesting ways of (mis-)using a common power amp to produce deliberate ...