Category: Blog

Temp Transmitters

Temperature Measuring Instrumentation

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…)

3 channels power supply

4-20 mA Loop Instrumentation

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

Basic 4-20 mA Current Loops

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


Using DC Current Shunts

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. The shunt has bolt holes or


Insulation Testing: Megohmmeter or Hipot Tester

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…)