In process industries, field contacts from pressure, temperature, flow switches, limit switches, push buttons, etc., are read by programmable logic controllers and/or distributed control systems (PLC/DCS) through digital input modules. They are ...
For decades, I’ve had a fascination with voltage-to-frequency converters and the 555 analog timer chip, and therefore a double obsession with VFCs based on the 555. In fact, my first Design Ideas (DI) submission (in 1974) was for a 555 VFC. ...
The pages of Design Ideas (DIs) have recently been awash in a veritable cascade of designs for variable frequency oscillators with frequency ranges tunable over multiple decades: Self-oscillating sawtooth generator spans 5 decades of frequencies ( ...
This project is an ultrasonic range finder built using the RP2040 Zero board and a 3.2-inch TFT display. It utilizes the RCWL-1655 sensor, which operates similarly to the popular HC-SR04, to measure distances ranging from 20 cm to 300 cm. The ...
A tiny DC to DC buck converter board is useful for many applications, especially if it could deliver currents up to 3 A (2 A continuously without heatsink). In this article, we will learn to build a small, efficient, and cheap buck converter ...
A while back I was challenged by a visitor to the website. He needed a very loud sweeping siren type audio sound generator powered by 3 V. He tried some of the commercial sirens but they were not very loud when powered by 3 V. He also said that ...
It is well known that a 555 timer in astable mode can be frequency modulated by applying a control voltage (CV) to pin 5. The schematic on the top of Figure 1 shows this classic 555 VCO. Modulating pin 5 has some severe drawbacks: The control ...
This two-part Design Idea (DI) follows on from a couple of previous articles relating to 100-Ω platinum resistance temperature detectors (Pt100 RTDs). The first of those (which we’ll call Ref 1 ) used a simple current-driven bridge to give an ...
The circuit uses a very inexpensive C-MOS IC that is connected to a small photodiode. Using a unique inductive feedback network, the circuit provides high sensitivity under high ambient light conditions. It is a great circuit when you want to ...
My recent DI contribution (Another silly simple precision 0/20 mA to 4/20 mA converter, Ref. 1 ) used the LM337 regulator in a novel circuit arrangement to translate an input 0-20 mA current source into a 4-20 mA two-wire transmitter current loop ...