| 摘要 |
<p>To control the temperature of, for example, a hot melt glue gun having a thermistor and calibration resistor R5 providing a signal representing actual temperature, a reference voltage for comparison therewith in IC1 is provided by a plug-in resistance module 16. The module 16 can be exchanged for another simular module to provide a different reference temperature, e.g. for a different glue, thereby avoiding recalibration of the glue gun. The result of the comparison controls a heater 18 via a triac 22. If no module 16 is present the glue gun is set at its lowest working temperature. <IMAGE></p> |
