Circuits & Schematics - Measurement - 5

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 ...

While refurbishing an ageing audio mixer, I decided that the level meters needed special attention. Their rather horrible 100 µA edgewise movements had VU-type scales, the drive electronics being just a diode (germanium?) and a resistor. ...

Awhile back I published a simple design idea for a thermal airspeed sensor based on a self-heated Darlington transistor pair ( Ref. 1 ). See Figure 1. Figure 1. Older design idea with self-heated Darlington thermal airflow sensor. In the circuit, ...

Capacitance sensors measure a wide variety of physical quantities, such as position, acceleration, pressure and fluid level. The capacitance changes are often much smaller than stray capacitances, especially if the sensor is remotely placed. I ...

With just one leftover op amp or comparator, you can add a battery-condition indicator to your portable circuit design. To indicate the life in an aging battery visually, the circuit in Figure 1 varies the duty cycle and flash rate of an LED when ...