Hot melt adhesive applicator and temperature control circuit therefor.

摘要

A hot melt adhesive applicator operable at a number of selected temperatures having a portion of the circuitry for control of the applicator temperature at a point remote from the applicator body. The remotely located circuitry employs a differential amplifier 39 and a zero crossing detector 38 for controlling the operation of a triac 41 which, when turned on, increases the temperature at the applicator. The differential amplifier 39 is protected by a clamping circuit 66-68 from receiving a signal, when a temperature setting is changed from a high to a low setting, that would otherwise cause the differential amplifier 39 to provide an output required for turning on the triac 41 which would cause a run away condition to exist.