Frequency-to-current converters accept a frequency (an AC signal) and produce an output current whose value is a function of the input frequency

Electrical current sensors measure AC and/or DC current levels.

Current-to-voltage converters scale and convert current signal input to the desired output voltage range

Frequency-to-voltage converters accept a signal and convert its frequency to a corresponding analog voltage level

DC-DC converter chips provide a regulated DC voltage output from a different, unregulated input voltage.

Phase-locked loop (PLL) frequency synthesizers are electronic devices that produce frequencies coherent to a reference frequency

Power supplies are devices that produce AC or DC power.