Circuits & Schematics Measurement - 14

The simple circuit in Figure 1 uses a low-current-drain MAX4073H amplifier to sense the current flowing through a 4- to 20-mA loop. The circuit senses the current through a 1 Ω resistor with a fixed gain of 100 and uses no battery or dc power ...

Designers sometimes need to analyze the spectrum of a modulated carrier. Although they can do this by down-converting and then digitizing and signal processing in the digital domain, the high-speed analog-to-digital converter (ADC) and the ...

Designers often use thermistors rather than other temperature sensors because thermistors offer high sensitivity, compactness, low cost, and small time constants. But most thermistors' resistance-versus-temperature characteristics are highly ...

You use high-side current monitoring in many battery-powered products that require accurate monitoring of load current, charger current, or both. In applications for nonportable designs, high-side-current monitoring serves as a power-supply ...

The human eye is remarkably sensitive to changes in light level. In ambient light ranging over several orders of magnitude, the eye can detect changes of only a few percent, yielding an incredible dynamic range. The primary trick is that the ...

An ac-based continuity tester for front-line test-and-repair jobs provides a simple go/no-go test for localizing faults in multiconductor cables (Figure 1). Open circuits are more likely to occur at the connector ends. This tool helps to identify ...

One of my go-to diagnostic tools is a simple home-brew audible ohmmeter (AudOhm). This circuit has served me well for many years, allowing “heads up” testing of wiring harnesses and control equipment, and various components such as ...

Some sports enthusiasts want to know altitude changes from an initial elevation. A small, lightweight, portable altimeter is easy to design using modern micromachined pressure transducers. Inverting barometric pressure and compensating for ...

Engineers have long known how to test a cable for continuity by simply connecting all conductors in series and checking with an ohmmeter. This method is sometimes impractical, however, because it cannot check for short circuits. The method shown in ...

The original application for the circuit in Figure 1 was to check the number of revolutions of an engine with only one LED as an indicator. The measurement of the number of revolutions usually involves sensors with a frequency output proportional ...