Circuits & Schematics

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 ...

Given two batteries, it chooses the one to connect to the load based on the voltage measured at their poles. It can also be used to switch DC power supplies. The growing demand for portable devices capable of working where there is no power grid or ...

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) ...

Figure 1 shows a simple tester, based on an ATtiny202 , a piezo buzzer, and an LED, for checking circuit wiring or tracing out the tracks on a PCB: Figure 1. The Tiny Continuity Tester based on an ATtiny202. The piezo speaker is on the reverse of ...

Let’s melt metals using the ZVS (Zero Voltage Switching) technique applied to a 1,000 W RLC resonant circuit. Have you ever wondered how intense the electromagnetic fields surrounding us can be? This is a relevant question, considering we are ...

Tracking down rodentia (or otherwise)-caused cable cuts, and differentiating them from normal open circuits, is critical. Evolving the circuit design for expanded functionality makes it even more valuable. It’s just part of the job. Every ...

In the first part ( Ref. 1 ) of this Design Idea, we saw how a cheap op-amp can give remarkably precise readings from an RTD. We also found that it was a false economy, owing to incurable thermal drift. This concluding part fixes that problem by ...

In the first part ( Reference 1 ) of this Design Idea (DI), we looked at simple ways of keeping critical components at a constant temperature using a linear approach. In this second part, we’ll investigate something PWM-based, which should be ...

If your favorite tool is a hammer, every problem will look like a nail. Abraham Maslow Given how often I tinker with the LM555 and LMC555 analog timers, Maslow might have written that famous aphorism specifically for me. And it. Well, here I go ...