RF amplifiers are electronic devices that accept a varying input signal and produce an output signal that varies in the same way as the input, but that has larger amplitude. RF amplifiers generate a completely new output signal based on the input, which may be voltage, current, or another type of signal. Usually, the input and output signals are of the same type; however, separate circuits are used. The input circuit applies varying resistance to an output circuit generated by the power supply, which smoothes the current to generate an even, uninterrupted signal. Depending on load of the output circuit, one or more RF pre-amplifiers may boost the signal and send the stronger output to a RF power amplifier (PA). Other types of RF amplifiers include low noise, pulse, bi-directional, multi-carrier, buffer, and limiting amplifiers. Detector log video amplifiers (DLVAs) are used to amplify or measure signals with a wide dynamic range and wide broadband. Successive detection log video amplifiers (SDLVAs) are log amplifiers that can operate over a wider dynamic range than DLVAs, while extended range detector log video amplifiers (ERDLVAs) are DLVAs that can operate with a wider operating frequency.