A balanced crystal oscillator circuit comprising: a piezoelectric element Xtal (207; 215; 222,221; 313); a first oscillator subcircuit (202; 210; 218; 302) incorporating a transistor (204;212;220;304); and a second oscillator subcircuit (201;209;217; 301) incorporating a transistor (203; 211; 219; 303); wherein the transistors each have different types of transistor terminals (C,B,E; D;G;S), and wherein the oscillator subcircuits are configured with at least three interconnections. Each interconnection comprise a pair of like type of transistor terminals; wherein a first of said interconnections constitutes a connection to a ground reference (gnd); a second of said interconnections is via a first resonator element (207;215;223;313); and a third of said interconnections is via a second resonator element (208;216;224;314); said first and second circuits are arranged to interact by means of said first and second resonator elements to form a balanced oscillator signal. A dual common base or a dual common collector configuration is preferred.