Device for Controlling the On and Off Time of the Metal Oxide Semiconductor Field Effect Transistor (MOSFET), A Device Spark Coating the Surfaces of Metal Workpiece Incorporating the Said Control Device and a Method of Coating Metal Surfaces Using the Said Device

Abstract

The present invention is a device for coating surfaces of metallic work pieces with an electrically conductive material by employing short duration high current packets of pulses in which the work piece forms the cathode and the consumable coating material forms the anode, which are connected to a generator for generating pulses by charging and discharging a bank of capacitors using a MOSFET. The invention is also a device for controlling the on and off time of a metal oxide semiconductor field effect transistor (MOSFET)

The invention claimed is: 
     
         1 . A device for controlling the on and off time of the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) comprising a pulse generator for generating packets of pulses, the pulse generator having one terminal connected to the MOSFET, and another terminal connected to a rotary selector switch, the rotary switch operative for selection of predetermined pulses, their amplitudes and pauses referred to as “mode”, the pulse generator also controlling the selection of an integrated circuit switch (I.C. switch) for selection of mode through another integrated circuit switch driver device, the I.C. switch acting as a multiplexer and being connected to a set of variable resistors through a pulse tuning device and a timing capacitor to a pulse generator device for controlling on and off time of the pulses that drives the MOSFET, the pulse tuning device including a set of variable resistors for each mode, a positive and a negative supply being fed to the variable resistors for charging and discharging pulses from a pulse generator device. 
     
     
         2 . A device for controlling the on and off time of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) comprising:
 a pulse generator for generating packets of pulses that control an on and off time of MOSFET;   a set of variable resistors for controlling the selection of the packets of pulses, their amplitudes and pauses generated by the pulse generator; and   means responsive to the pulse generator for selecting a subset of the resistors thereby selecting the packets of pulses, their amplitudes and pauses generated by the pulse generator.