| 摘要 |
<p>The energisation of a heating element 1 is controlled in dependence upon a comparison of an actual-value signal (from a sensor 2) and a signal which is the sum of a set-value signal (from a reference source 8) and the output of a fixed-frequency triangle wave generator 6 which is amplitude modulated in dependence upon the rate of change of temperature. The effect is to produce a proportioning range (within which the mean power to the heater 1 is proportional to the error between the actual and set values) which is dependent upon the rate of change of temperature and which is therefore reduced as the set value is approached. The circuit produces good dynamic performance without instability, and may be used in applications other than temperature control, e.g. a servo system. <IMAGE></p> |
