RMS to DC converters are devices that performs an RMS AC voltage signal to DC voltage signal conversion. They are used in applications where precision or low power measurements of AC signal levels are required. The DC output voltage of the device typically equals the RMS value of the AC input voltage. They typically operate over a broad range of frequencies of input AC. 

 

RMS stands for root mean square. It is the square root of the mean of a sample set of measurements that are squared. RMS is important because it is the standard way of measuring a signal level, and when it compares it to the characteristic impedance, it is a measure of the power of a signal. AC waveforms of different shapes have different RMS values – but with talking about their RMS levels we have a common measurement technique.

 

RMS to DC converters usually have an extremely high impedance input FET to reduce input on the circuit being monitored. The RMS block incorporates precision full wave rectifier and a log-antilog transistor array for squaring and square rooting to calculate the RMS value. Due to the large range of input waveform shapes and amplitudes it is important that the converter has a wide dynamic range. They may require a simple single pole passive filter on their output to reduce the output residual ripple. Typically RMS converters have a high-quality output buffer that can be configured to non-invert, invert the RMS value or even operate in a current output option.