Circuits & Schematics - Measurement - 10

On June 12, 2011, the analog EE world lost a star when guru James M. Williams died. Jim’s hundreds of articles, books, and application notes were (and continue to be) a bottomless wellspring of information, inspiration, and the joy of seeing ...

CMOS devices have large input impedance with input currents on the order of 0.01 nA. Adding feedback circuitry can result in a latch-like device that can be used to store bits, and also operate in a more analog mode as shown in this Design Idea, ...

In the proximity detector of Figure 1, a 4-in.-sq piece of copper-plated pc board serves as an antenna that forms one plate of a capacitor. An approaching (grounded) person serves as the other plate, producing a capacitance value of 2 to 5 pF that ...

Introduction A 500 V protection circuit for low voltage high impedance measuring instruments is shown in Figure 1. The protection is accomplished by limiting the amount of current going into the measuring instrument. The circuit will protect ...

Recently, I’ve been working on a solar off-grid monitoring system. In the system are a few split-core Hall effect sensors to monitor DC current in the solar panel current, the battery charge current, and the inverter input current. These ...

Figure 1. Common view of the Precision Thermocouple Amplifier board. This precision thermocouple sensor module performs cold-junction compensation and digitizes the signal from any type of thermocouple. The output data is formatted in degrees ...

This Design Idea describes a handy continuity tester with two modes of operation: It may sound if it detects continuity between its two probes, or it may sound when it detects no continuity. The second option permits testing for intermittent cable ...

The autoreferencing circuit in Figure 1 nulls out the error of a sensor, such as a pressure transducer, at its reference level for example, at ambient pressure. The circuit is an analog-digital-feedback control system that uses a digitally ...

Piezoelectric transducers find use in NDE (nondestructive-evaluation) applications. The PVDF (polyvinylidene-fluoride) transducer has many advantages, including a wide bandwidth and high sensitivity. These transducers require high-voltage and ...

To measure a zener diode’s breakdown voltage, you need a dc voltage source whose voltage exceeds that of the zener voltage. In Figure 1, resistor R SER provides voltage drop between V IN and V ZEN . In any case, V IN should exceed V ZEN . ...