Circuits & Schematics - Measurement - 10

This article describes an active load circuit that can be used to simulate a battery in any state of charge. The battery simulator provides a constant-voltage load for a battery-charging circuit, independent of applied charging current. The ...

It is often desirable to determine a battery’s internal resistance to evaluate its condition or suitability for an application. Accurate battery resistance determination is complicated by inherent capacitive terms which corrupt results taken ...

Self-heated thermal airflow sensors are simple, cheap, rugged, and sensitive. However, they exhibit an airspeed to sensor temperature response ( King’s Law ) that is very nonlinear, as shown in Figure 1. Figure 1. The TO-92 junction ...

I was reminded recently of a tester I designed years ago. At the time, I wanted to build “The Ultimate Continuity Tester,” and I established a wish list of all the features I required: A “real continuity” tester. Too many ...

Low-power, low-cost ceramic piezoelectric rate gyros are available, but they lack the low-temperature-coefficient characteristics of their quartz counterparts. However, you can use a servo amplifier to remove the dc level shift due to ...

Figure 1’s circuit achieves a wider dynamic range and higher output frequency than any commercially available voltage to frequency (V-F) converter. Its 100 MHz fullscale output (10% overrange to 110 MHz is provided) is at least ten times ...

No currently available V-F converter will accept bipolar (AC) inputs. This feature is desirable in power line monitoring and other applications. Figure 1’s V-F converter accepts 10 V inputs, producing a 0 kHz to 10 kHz output. Linearity is ...

The circuit in this Design Idea anticipates, or jumps instantly to, the final voltage of an input-signal change. It relies on the fact that the intended input signal changes exponentially with a known time constant. This circuit was adapted from a ...

In a three-phase ac system, a power source with three wires delivers ac potentials of equal frequency and amplitudes with respect to a zero-potential wire, each shifted in phase by 120 from one wire to the next. Two possibilities exist for ...

The advent of instrumentation amplifiers with digital gain switching offers obvious advantages, such as board-space saving, higher reliability because of fewer solder joints, and lower total cost. These valuable features stem from the fact that the ...