Circuits & Schematics

When the Sun is shining and illumination is needed inside a dimly lit interior space, a popular, proven, and highly efficient solution is to utilize the energy of available sunlight in the simplest and most sustainable fashion conceivable: Opening ...

Battery-operated instrument benefited from auto-power shutdown A handheld, battery-operated “fiber finder” measures the light escaping from an optical fiber when clamped in a V-shaped block under slight pressure. A pair of photodiodes ...

Figure 1 shows two large-signal- measurement methods. The first uses a two-resistor voltage divider and an output buffer, and the second comprises an attenuating inverter and a high-value input resistor. Both of these approaches introduce ...

All thermal anemometers work by inferring air speed from measurements of thermal impedance (Z) between a heated sensor and the surrounding air: (1) where P is the power dissipated by the sensor and T is the temperature difference between the sensor ...

In Part 1 ( Ref. 1 ) of this article, we briefly looked at the Wien bridge oscillator before homing in on the bi-quad filter as our best candidate for an oscillator capable of giving 0.0001%/ 120 dB distortion, and showed its full circuit. Treating ...

Over the years, the Design Ideas (DI) column has featured many interesting oscillators, but none that I can recall was specifically designed to produce a really clean sine wave. Putting that omission together with the need to rebuild my old ...

The popular I 2 C communication standard manages to perform flexible serial I/O with just a super simple two pin bus: SCL and SDA. It accomplishes this trick with bidirectional timing and data flow. Bidirectional flow is good at saving pins but due ...

Several years ago we were developing a clamp-on photometer, a hand-held instrument that could be clamped onto a communications optical fiber to indicate the presence of light, its direction of travel, and the presence of combinations of ...

When a system's specifications call for a lowpass filter with a steep frequency-cutoff characteristic, an engineer can opt for a “brick-wall”- filter design that features a sharp transition band. For example, in an FM ...

The basis for this Design Idea is a circuit that uses three resistors and a microcontroller-I/O pin to work as input high impedance or output to independently drive two LEDs ( Reference 1 ). The idea sounded good for this design, mainly because of ...