Circuits & Schematics - Measurement - 14

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 ...

A self-biasing thermistor circuit had an overall dominant thermal/ electrical time constant as small as 25 msec but had a significantly rounded response following a square (thermal) input pulse of 100 msec; the source was a pulsed blue LED. A ...

Solid-state-lighting applications are quickly moving into the mainstream. Although they are more efficient, the LEDs that produce the low-cost light often require a complicated driver circuit. Testing the driver circuit using LEDs, although easy, ...

You may lack experience and hardware when designing battery-operated products. The battery life of a product can depend more on the ESR (equivalent series resistance) than the terminal voltage. This situation is especially true when you use ...

Figure 1 is a micropower voltage-to-frequency converter. A 0 V to 5 V input produces a 0 kHz to 10 kHz output with a linearity of 0.05%. Gain drift is 80 ppm/ C. Maximum current consumption is only 90 µA, almost 30 times lower than currently ...

Analog circuits for long-term testing of passive components, such as 0.1%-tolerant resistors or high-intensity white LEDs, often require a constant current. Using two op amps and a voltage reference, you can develop a circuit that provides a ...

The standard way of using an RTD (resistance-temperature-detector) sensor is to include it in a bridge followed by a differential amplifier. The problem is that two nonlinearities one from the sensor and another from the bridge affect the transfer ...

In power supplies or battery chargers, you often need information about the current flowing in the high-side rail. Figure 1 shows a common circuit for obtaining this information. Figure 1. This method for measuring high-side supply current requires ...