Circuits & Schematics - Measurement - 7

Self-heated transistors used as thermal air flow sensors are a particular (obsessive?) interest of mine, and over the years I must have designed dozens of variations on this theme. Figure 1 illustrates one such topology seen here (Reference 1) ...

Anemometers are an important category of environmental sensor. Articles about their design, data capture, and linearization have comprised topics featured in EDN Design Ideas, several quite recently. Less well covered, however, has been the topic ...

An obstacle detection unit is an essential part of a variety of projects, such as robotics and security applications. The infrared sensors are widely used for these types of applications. The main drawback of some circuit designs is that the ...

Awhile back I published a simple design idea for a thermal airspeed sensor based on a self-heated Darlington transistor pair (Ref, 1). The resulting sensor is simple, sensitive, and solid-state, but suffers from a radically nonlinear airspeed ...

At the end of the DI for a Simple log-scale audio meter (Ref. 1), I promised to show how to upgrade it to work better. With these fixes, it now has near-digital performance, with faster response and smoother operation. Even this supersized version ...

The logic probe is powered from the device under test (DUT) it may be any binary logic, which can be powered in the range +2 V to +6 V. This may be a microcontroller or 74/54 series logic chips, including HC/HCT chips. The probe determines 3 ...

Differential temperature measurement is a handy way to quantify the performance of heatsinks, thermoelectric coolers (TECs), and thermal control in electronic assemblies. Figure 1 illustrates an inexpensive design for a high-resolution differential ...

Conventional thermostats are based on separate temperature sensor and heater devices with means for feedback between them. But in some recent EDN design ideas (DIs) we’ve seen thermostat designs that meld the functions of sensor and heater ...

Evaluating analog switches, multiplexers, operational amplifiers, and other ICs poses challenges to IC-test engineers. A typical test scenario requires application of a test or forcing voltage to a device's input and measurement of any ...

Fig 1’s circuit, which was developed to monitor the traffic of bumblebees into and out of the hive, differentiates “a-to-b” motion from “b-to-a” motion. When used with an optical decoder, the circuit distinguishes ...