A synchronous detector electronics package with self‐contained oscillator is described. It uses only three integrated circuits, all of which contain operational amplifiers. The performance of the detector was evaluated with a capacitance sensor. Linearity and stability were found to compare favorably with general purpose commercial systems costing hundreds to thousands of dollars. Although the noise performance was less impressive, the dynamic range was still in excess of 90 db, permitting better than 100 &mgr;rad resolution over a range of nearly 3 rad. As presently configured, the detector is compatible only with high impedance sensors such as the capacitance type; however, coupling the oscillator output through a power amplifier would permit its use with LVDTs.