Having manufactured wire wound resistors for well over 50 years there are very few applications that we have not come across. Current sensing resistors are often required in applications from motor speed control, electric motor overload sensing circuits and the likes. With the increased uptake of solar power in Australia in recent years, both off grid and grid connected there have been a number of local manufacturers (particularly in South Australia), involved in the manufacture of solar inverters ranging from 50 watts up to several kilowatts. One of the requirements of switch mode solar inverters is the need for a low ohm current sensing resistor. It is needed to measure inverter voltages without consuming significant power, which, in a solar system, is obviously important not to ‘waste’ any of the solar power generated by the solar panels.
FSR Series Current Sense Resistors
The FSR series current sense resistors (pictured below) are specifically designed as a very flexible, low cost and high reliability current sense resistor. The are available in a 3 watt (FSR-03) version or a 5 watt (FSR-05) version. In the case of the FSR-03, they are available is resistances from 0.05 ohms to 0.01 ohms and the FSR-05 from 0.005 ohms to 0.05 ohms.
These are ideal for any power conversion applications, including inverters and are available on short lead times.