Here are some comments of Dr. Peter Lindemann on this concept:
But let's start at the beginning. What was Tesla trying to do? He was trying to produce a simple DC square-wave pulse train. But he didn't have ANY electronic control devices. No 555 timer chips. No transistors. No vacuum tubes. He only had coils, capacitors, mechanical contacters, and spark gaps.
So, what does Tesla's longitudinal electrostatic wave-front look like? It looks like a DC square-wave pulse train where the pulse repetition rate is one million impulses per second, the duty-cycle is 10% On and 90% OFF, and the voltage in each impulse is 50,000 volts DC or more. This is what Tesla wants the circuit to do. This is what he wants to create by the discharge of his capacitor stage in the circuit.
So, if the spark gap is his "circuit controller" then he only wants a "single crack" each time the capacitor discharges. Just a single, unidirectional impulse of electrostatic charge to proceed forward before the circuit shuts off again. Then, the capacitor can charge up again for the 900 nanoseconds the spark gap is quiet and then discharge all of the stored energy again in 100 nanoseconds. Then repeat indefinitely.
It creates a "staccato of electrostatic bursts." Don't make this mysterious, because it is not. It is no more difficult to understand than the output of a 555 timer chip. Its just that we are talking about very high voltage DC, and very high pulse repetition rates. What is difficult is finding the circuit components that allow you to create these conditions without self-destructing!
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Steve