Abstract: A temperature-compensated crystal oscillator utilizing a fundamental frequency crystal with an input RC network to bias an input transistor. Temperature compensation for the oscillator is achieved by the use of a series diode in the emitter circuit of the input transistor. As the temperature changes, the emitter-to-base voltage varies and causes the emitter current to vary in the opposite direction. The voltage across the series diode tracks with the emitter-to-base voltage in the same direction. With these occurrences, the emitter-to-collector voltage is controlled and stabilized over a range of temperature changes. The parallel RC circuit which couples the input transistor to the output drive transistor provides the necessary base current and input impedance for the output trnasistor to permit saturation of and wave shaping by the output drive transistor.