An electrometer preamplifier for the measurement of dc voltage, current, and resistance in high resistivity materials has been developed. The ranges of measurement for voltage, current, and resistance are from 30 μV to 10 V, 10-2 to 10-13 A and 103 to 1013 Ω, respectively. Charge measurements can also be made by connecting a suitable capacitor in the feedback loop. It uses commerically available operational amplifiers. The preamplifier is small in size and is used in conjunction with a commerical voltmeter or recorder. It is ideally suited for in situ measurement of electrical properties of amorphous semiconductor films.