Articles - Measurement - 3

One of the first problems a capacitive-sensor analog designer must face is the low-frequency cutoff. Theoretically, you must fulfill just one simple requirement: a sufficiently large input resistance of the preamplifier's first stage. In ...

A bi-directional current source for a grounded load will always have some complication in its construction. The improved Howland Current Pump as shown in Figure 1 is the most frequent choice for this function. The Howland requires carefully matched ...

Despite the increasing availability and declining cost of on-chip analog peripherals, the humble PWM DAC retains its appeal as a “free” DAC [ 1 ] that can repurpose an uncommitted DIO pin and counter/timer module, add a simple low pass ...

The circuit in this Design Idea was originally designed to detect damaged conveyor belts in the mining industry. Thin coils are embedded in the conveyor belt. If the belt suffers damage, it stretches at the affected location, causing one or more ...

Trying to shield ambient light from your photo circuit is not a trivial task. You would think that you could just cover your circuit with your hands, but that is not a solution: Pulse oximeters depend on the translucency of flesh. Covering the ...

This article will describe how Bode plots can be used as a tool to quickly assess if your power supply design will meet the requirements for dynamic control behavior. Power supplies normally maintain a fixed output voltage via a control loop. This ...

The pressure-sensor amplifier circuit of Figure 1 offers a number of advantages over the traditional approach using the classic three-op-amp instrumentation amplifier. The circuit can operate from a single supply and uses only two op amps and 1% ...

In test-and-measurement applications, you must provide overvoltage protection for the output terminals of amplifiers, power supplies, and similar components. The conventional way to accomplish this task is to add series resistors with the output ...

Introduction Current-sense resistors, which come in a variety of shapes and sizes, are used to measure current in many automotive, power control, and industrial systems. When using very low value resistors (a few milliohms or less), the resistance ...

While measuring op-amp input capacitance, what should you focus on? The answer is that you must ensure the measurement accuracy isn’t degraded by the stray capacitance and inductance of the PCB or test setup. You can minimize these issues by ...