| 摘要 |
PCT No. PCT/AU84/00171 Sec. 371 Date May 8, 1985 Sec. 102(e) Date May 8, 1985 PCT Filed Sep. 7, 1984 PCT Pub. No. WO85/01367 PCT Pub. Date Mar. 28, 1985.Apparatus for controlling the current flow through metal foil heating elements in carpet joining tape comprises an oscillator which produces a high frequency output to drive a power amplifier so that the output voltage to be applied to the heating element is at a frequency proportional to or the same as the oscilltor frequency. The output current (Rms) value is controlled by controlling the pulse with using a modulator which either increases or reduces the output pulse width in accordance with a comparison of the sensed output current against a reference derived from a control circuit. The reference voltage is dependent on the operating mode of the apparatus selected by switches or switch and counter. |
