TH Crystal Oscillators

A through hole (TH) device is any component that is packaged in a way that allows the leads to be threaded through a hole in a circuit board and then soldered to pads on the opposite surface of the board.  This is in contrast to a surface mount device where leads are soldered directly to the pads on the surface of the board.  A crystal oscillator is a device that relies on the piezoelectric and resonant properties of crystals to generate an electrical signal that repeats at a precise frequency.  Applying an electrical potential to a crystal causes electrical stress that induces a brief vibration.  Sustained resonance can be obtained by amplifying the resulting electrical signal and feeding it back into the crystal.  This process results in an electrical oscillator that is extremely stable and temperature independent.