Circuits & Schematics Measurement

The LM324 is a cost-effective choice for an op amp, especially when you need to apply ground-level inputs. Although its output purportedly includes ground, its poor current-sinking capability limits the applications. At output voltages lower than ...

Battery-operated equipment often requires a low-voltage monitor to warn the user when the battery voltage is too low or to perform other functions, such as power-source switching or device shutdown. Many specialized ICs are available to satisfy ...

You can improve a capacitive-sensor circuit with a modulator and an RF transmitter (Reference 1) by modifying the modulator portion to obtain better accuracy. More improvements result from adding a “negatron” circuit, a configuration ...

The circuit in Figure 1 is a triple, relative-humidity sensor and radio transmitter. Sensors 1 and 2 form two gated oscillators with natural frequencies of 10 and 5 kHz, respectively, at relative humidity of 50%. The gated oscillators use variable ...

You can achieve accurate resistance-temperature-detector sensor measurements without having to resort to using a precision current source. Traditionally, resistance-temperature-detector (RTD) sensor resistance is measured by applying a precision ...

The availability of a seemingly limitless variety of monolithic DAC chips makes it easy to implement most digital-to-analog-conversion applications with a single off-the-shelf device. Sometimes, an unusual set of requirements necessitates a ...

Testing power supplies and batteries requires current loads capable of sinking large current and dissipating substantial amounts of power. A simple but accurate current load can be built using just a single op amp and a power MOSFET, as shown in ...

Plumbing a laboratory with a standard frequency makes a lot of sense if the lab uses multiple frequency counters, spectrum analyzers, and other frequency-dependent test equipment. Rather than spending time keeping all of the instruments' ...

In a water-cooled power converter, analog-output sensors measure the cooling water temperature at three locations. If any of the three temperatures rises above a preset threshold, an alarm sounds and attracts the attention of the system's ...

The simple circuit design in Figure 1 lets you measure all components of a current flowing in a dc servo motor. The rectified output of the circuit uses ground as a reference, so you can measure the output by using a single-ended A/D converter. The ...