Discusses simple interval timers for microcomputers, including (1) the Jiffy clock; (2) CPU count timers; (3) screen count timers; (4) light pen timers; and (5) chip timers. Also examines some of the general characteristics of all types of timers. (JN)

Describes hardware and software requirements for interfacing a thermometer probe, via an analog and digital converter, to any Commodore PET, VIC-20, or Commodore-64 microcomputer (or other microcomputers with some modifications). Also describes use of the probe in an experiment measuring enthalpies of reaction to determine enthalpy of formation of…