The Weschler Temperature Measurement application note reviews the characteristics of popular sensors used to measure temperature: thermocouple, RTD (resistance temperature detector), thermistor, semiconductor, and infrared. This article surveys the instrumentation used in conjunction with these sensors for industrial temperature measurements. (more...)

Three devices are needed to make a 4-20 mA current loop – a transmitter, receiver and loop power supply. (more...)

The current loop is a widely used industrial control circuit topology. The basic current loop has three elements:

• A transmitter that sends a dc current around the loop
• A receiver that measures the current in the loop
• DC voltage supply that powers the loop
(more...)

A DC current shunt is a specialized resistor used to measure high currents. The shunt is wired in series with a heavy load, such as a DC motor, battery charger, heater, plating bath or smelter pot line. A DC voltmeter is connected to the shunt in a 4-wire (Kelvin) configuration. (more...)

There are two common methods for performing insulation tests on cables, wiring and electrical equipment. One uses a megohmmeter to measure insulation resistance. The other uses a hipot tester to check for insulation breakdown. Both apply a high voltage, either ac or dc, to the device under test (DUT) and measure the resulting current flow. (more...)