Patent ID: 7821348

Claim:
A crystal oscillator for surface mounting, the crystal oscillator comprising: an oscillator circuit comprising: an IC chip comprising an output circuit and a function circuit; and a crystal element comprising: a first excitation electrode on a first surface thereof; and a second excitation electrode on a second surface thereof, which is opposite to the first surface; a main body, which houses the oscillator circuit and the crystal element such that at least the crystal element is hermetically encapsulated therein, and which comprises a plurality of mounting terminals on an outer bottom face thereof, the plurality of mounting terminals comprising: a power supply terminal; a ground terminal; an output terminal; and a function terminal; a first switching circuit that is electrically connected to the output terminal; a second switching circuit that is electrically connected to the function terminal; and a voltage detecting circuit that is connected to the power supply terminal, wherein the output terminal is electrically connected to the output circuit and the first excitation electrode via the first switching circuit, wherein the function terminal is electrically connected to the function circuit and the second excitation electrode via the second switching circuit, and wherein the first switching circuit and the second switching circuit are operated on the basis of a switching signal from the voltage detecting circuit connected to the power supply terminal.