A collapsible folding stand for use with a portable table saw or other object that is attached to the stand and is capable of being manipulated between open and closed positions. The seat is vertically adjustable and held in place by a clamp. ZCD-signal is coupled to a blanking circuit, generating a blank-signal and a pulse-signal, controlling the switch. The present invention provides a method of tracing which can be applied to an HBES algorithm structure.