This inductive reactance is canceled or tuned out with the capacitive reactance. At series resonance, the impedance of the grounding strap to the earth ground as seen by the transmitter is thus minimized and limited by the ac resistance of the strap. With this capacitance, the ground at the transmitter is referred to as an artificial ground. The impedance of the transmitter’s chassis, which is connected to this artificial ground, to the earth ground, is thus smaller at the tuned frequency (but not necessarily at other frequencies) than without this capacitor. This helps keep RF “hot spots” from appearing on the chassis and tends to reduce RFI. It is important to note that by placing a capacitor in series with the grounding strap there is no dc path to ground through this strap. From a safety standpoint, there is a need for another low-frequency connection to ground that does not have a series capacitor.

 

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