try Hertz question / problem

I did today quickly Department work practical experiments with my physics prof before the holidays to my. at least we tried it...
radar is the main theme, experiments relate to the reflection experiments of heinrich hertz, 2 parade with spark gap & dipole in the focal point who will face off, at a mirror high-voltage source is connected ne which regularly spark, induced voltage in the antenna at the 2nd level...

in our case is the hv-an Influenzmaschine, source part fat, tighten 3 times and you have one hit over 3 cm: mrgreen:

the induced voltage can be measured by one just on the 2nd appends an oscilloscope to page, also on the weakest gain switches and switches the probe to 10 x, you get values with reasonable crowds the oszi hasn't hurt the but you can't say for sure whether the second mirror has anything to do so because the oscilloscope or the cable to the oscilloscope received the signal without parade & antenna. -.

does anyone of you idea what you could do ne? the cable to the oscilloscope should prevent exactly something like this as a coaxial cable or?
in the original, which was try with a coherer 2 carried out mirror, I might try that also, but that is cumbersome and it works I not so think as it should...
could you make some simple electronics for this? the secondary voltage ca 100V-200V might...
or fält what you insulate the pipe or similar? What could you as a display on the 2nd page use? Probably arise just 100... 200V against earth. That would explain the oscilloscope displays something like this.
The solution would be to use, but a different display circuit example no oscilloscope.
The easiest way a transistor that controls an LED for example.
The transistor needs a fairly large base resistor, for example 100kOhm.
And most important: from emitter to base even a diode, anode emitter and cathode for basic needs. It prevents the emergence of a negative voltage on the base, which would otherwise destroy the transistor.
You should then run the circuit with a battery or a rechargeable battery, so that it really has no connection to the Earth. The receiver provides sure more than a few µA. That should do it then.


Of course, you can take also a FET. But please no power MOSFET, but what small, z.B a 2N7000.
Power MOSFETs have indeed pretty much gate capacity.
The FET needs still a Zener diode from gate to source, so the gate gets no surge. And a resistance from gate to source would be good as well, so that the gate does not self-excite. So 10 mohm should be ok. I built even just the attempt by Hertz. A student thesis is also with me. With me to (round) wireless technology revolves.
For me, a spark went as an indicator. The range is although not too large with a few cm and the spark length is anything but big, but I can prove the radio waves. I can prove the reflection and shield the radio waves it. When I ne metal plate in between, is the spark in the receiver. I got when first also tried secondary spark to generate but I saw nothing there...


What are you used because as HV source? I've now even assembled my fritters, in an empty ink cartridge. Now the Bell must reasonably to iterate and then ancient radio receiver is my anno 1900 finished. at what time intervals than spark ignition coil?
does the fritters for decent work? If you want to transmit Morse code, you have to shake the fritters which with a Wagnerian hammer, so that the iron filings by the radio waves, is again zerstreun.

Have there 2 questions about high-voltage

1. you know, but these lines on the trains or trains to be powered. There, yes a current flowing from Let's say 16kV. Is that really true with 16kV spark can jump up to half a meter? In an accident by as a "surfer" able in the article. I can't believe that somehow.
2. how much mA must actually flow, so that one must reckon with damage of the eyes or blindness through the brightness? also "not special Commissioning jobs line voltage flows" a certain has potential to a point of reference, in which case warsch Earth, or you say it's up to the voltage xxxV

It may be that 50 cm long is the arc in the final analysis, but to ignite half meter in nem brauchts had far more than 16kV. You length of the arc is influenced significantly by the current fire distance from the voltage (knnst with n put some thick bleiakkus LiBos, see Hedgehog xD). One should differentiate between ignition distance and safety distance. An ignition would be 16kV at worst maybe in 5-10 cm distance, but typically in under 2cm. As a precaution however, you should keep a distance to live parts, which is far greater than the ignition distance. That exist appropriate regulations, I know but not by heart. Half a meter safety distance with 16kV seems the absolute minimum but, if you hang on his life.

EDIT: We must also never forget that other effects in play, which can also affect the ignition distance may. For example, the earthed roof of a train can make a capacity against the live wire, which evt. even small currents to flow and thus to ionize the air. The result is a higher electric field strength, which favors a rollover. are 15 kv 16 2/3 Hz. Safety distance of db 1.5 m. as kilovolt wrote, is that the safety distance min. must be maintained from the contact wire. This distance is but "actually" only for ma which, because otherwise no one in this small distance to the wire can come in db. I've seen since a video a while ago, where a person on the roof of a train runs around, and intentionally provides against the line. He went on to "Flame" and was dead within a very short time or completely burned. Only I can't find this video, probably it was deleted because it's so brutal.

If here about 16kV flow at a power of 10MW, enabling up to 625A flow (according to invoice). Is that actually true of human body resistance is not linear? Or higher voltage, so less resistance? Because at that time, as I the video saw where this person has gone up in flames, if the person has a resistance of 1kOhm E.g. enough already 16A with 16kV? So, the man practically represents a short circuit. Thank you for an explanation. It is important to not the power, but the performance, which will be implemented in the arc. Also the power density in the arc (i.e. how many Watts per cubic-inch plasma volume flow) is very important.
In electric welding this power density is very high, so the light is grellweiß and very bright. This can damage the eyes, although the performance is great only a few kW.
If you look, however, in a several meters long arc (for example) 1 mega Volt, 1A, which would be probably not so bad. Performance (1 MW) is much bigger here, but the temperature is low, because the power density is lower. Therefore the arc not as bright lights.

Yes, the body resistance is not linear:
At a few volts, he is so 100kOhm up to 2MOhm.
Mains voltage, the resistance of the skin is no longer effective, then there are still 1...10kOhm.
The water molecules in the body can be ionized more voltage. Then a conductive plasma channel through the whole body can be formed. The resistance can fall here estimated on a few ohms (something like that... is likely to end the but almost always fatal).