Computers are now widely used in many physics labs and classrooms for graphing, data analysis, timing, and temperature measurement. This paper presents some laboratory applications that are less widely used. Most of these applications require hardware to allow the computer to do voltage measurement. There are several types of devices that can accomplish this task, including analog-to-digital converter boards, voltage-to-frequency converters, and serial output analog-to-digital converter ICs that can connect to the game port. For some of the applications described, the voltage signal changes quickly and the voltage-input device must be capable of collecting data at a rapid rate. Some of the circuits described require +12 V and -12 V power supply lines. Others can operate off only a +5 V power supply lead. The AC control circuit is specific to the Apple II computer and requires no additional hardware.