Simple tuner for radio receiver - has nonlinear potentiometer applying nonlinear tuning volts to make varactor diode linear

摘要

The simple tuner, for radio receivers, consists of a potentiometer coupled by its slider to the varactor tuning diode and by its main terminals to a constant bias voltage. The potentiometer's resistance element is non-linear such that the varactor diode's non-linear voltage/capacitance properties are compensated. That is: a linear movement of the control knob that drives the slider results in a non-6inear biasing voltage and a linear change in tuning capacitance. The potentiometer's slider consists of a sprung wiper moved by the control knob over a curved non-linear resistance path.