A microcomputer-based programmable temperature controller

The authors have designed an automatic electronic temperature controller using an analog-to-digital converter, a digital-to-analog converter and a power device controlled by the phase of the power supply current. An Apple II microcomputer controls the heating or cooling in response to the digitized data, and can be set to control a wide range of nonlinear and repetitive processes. Need for continuous attention or manual adjustment is eliminated. Software programs developed in this system are simple to use and provide versatility in programming temperature ranges and timing of processes.