How does this tesla coil tuner work?

[boylesg]

https://www.rmcybernetics.com/projects/DIY_Devices/homemade_tesla_coil_tuner.htm

How is this meant work?

**broken link removed**

They say, when testing the secondary coil, you connect the leads in series between the coil and the ground connection.

Surely this thing would not put out enough voltage or current to get a detectable reading with a hanging connection?

Would they mean that you are meant to also connect the ground lead to the torroid?

 

[jiripolivka]

https://www.rmcybernetics.com/projects/DIY_Devices/homemade_tesla_coil_tuner.htm

How is this meant work?

**broken link removed**

They say, when testing the secondary coil, you connect the leads in series between the coil and the ground connection.

Surely this thing would not put out enough voltage or current to get a detectable reading with a hanging connection?

Would they mean that you are meant to also connect the ground lead to the torroid?

The "tuner" is a device which can indicate resonance frequency of a circuit connected to the test terminals. The resonance is indicated by the two LEDs.
Tesla transformers and other similar circuits operate best at resonance. Once you find their resonance frequency, you can design the power driver for it.
Read carefully the description and operation of the Tuner, it says everything you need to know.

 

[boylesg]

The "tuner" is a device which can indicate resonance frequency of a circuit connected to the test terminals. The resonance is indicated by the two LEDs.
Tesla transformers and other similar circuits operate best at resonance. Once you find their resonance frequency, you can design the power driver for it.
Read carefully the description and operation of the Tuner, it says everything you need to know.

Yeah but it doesn't tell me how 9VDC, or what ever comes out of the 555, can cross the air gap between the torroid and the ground connection.

Or how the test circuit is complete in some other way when testing the secondary coil.

 

[FvM]

As far as I understand you are expecting a parallel resonance of the secondary coil, If so, the tester would be connected to both coil ends.

 

[boylesg]

As far as I understand you are expecting a parallel resonance of the secondary coil, If so, the tester would be connected to both coil ends.

Unless I misunderstand the following then the tester is not connected to both ends of the secondary coil.

**broken link removed**

 

[jiripolivka]

Unless I misunderstand the following then the tester is not connected to both ends of the secondary coil.

**broken link removed**

Due to the large inductance of the secondary coil,the "air gap" makes for the capacitAnce that resonates with the coil.

 

[boylesg]

Due to the large inductance of the secondary coil,the "air gap" makes for the capacitAnce that resonates with the coil.

Wow! That is a surprise then. I wouldn't have dreamed that that woukd be possible with a 9V battery.

 

[jiripolivka]

Wow! That is a surprise then. I wouldn't have dreamed that that woukd be possible with a 9V battery.

The resonance has not much to do with the battery voltage. At resonance the current drawn into the tested circuit through the two LEDs increases, and can be indicated.
A similar principle used at RF is the old "grid-dip" or newer "dip meter". An oscillator coil coupled to a tested resonant circuit transfers the RF energy with a peak at resonance. The "dip" is indicated by RF detector (voltmeter) connected to the primary RF coil.

 

[boylesg]

The resonance has not much to do with the battery voltage. At resonance the current drawn into the tested circuit through the two LEDs increases, and can be indicated.
A similar principle used at RF is the old "grid-dip" or newer "dip meter". An oscillator coil coupled to a tested resonant circuit transfers the RF energy with a peak at resonance. The "dip" is indicated by RF detector (voltmeter) connected to the primary RF coil.

I am entirely accustomed to comprehending closed circuits thus far. So this open circuit situation is a little anti intuitive for me.

 

[jiripolivka]

I am entirely accustomed to comprehending closed circuits thus far. So this open circuit situation is a little anti intuitive for me.

So you can take the secondary coil with its stray capacitance as a quarter-wave antenna.

 

[boylesg]

So you can take the secondary coil with its stray capacitance as a quarter-wave antenna.

Oh OK! Thinking of the secondary coil and torroid as an antenna makes a lot more sense to me. Thanks.

 

[FvM]

Due to the large inductance of the secondary coil,the "air gap" makes for the capacitAnce that resonates with the coil.

Sounds unlikely. Even with open coil, the resonance frequency will be most likely dominated by the coil self capacitance, the air capacitance only adds up. Due to the "air capacitance", the resonance can be measured with a single ended connection.