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Re: Tank frequency
>Date: Tue, 8 Oct 1996 22:25:15 -0600
>From: Tesla List <tesla-at-poodle.pupman-dot-com>
>To: Tesla-list-subscribers-at-poodle.pupman-dot-com
>Subject: Tank frequency
>Reply-to: tesla-at-pupman-dot-com
>>From DavidF4797-at-aol-dot-comTue Oct 8 21:57:34 1996
>Date: Tue, 8 Oct 1996 10:24:12 -0400
>From: DavidF4797-at-aol-dot-com
>To: tesla-at-poodle.pupman-dot-com
>Subject: Tank frequency
>In response to Kyle Chadwick, it was mentioned that the ocilation frequency
>of the "tank" circuit is primarily a function of the inductance (L) of the
>primary coil and the capacitance (C) of the tank capacitor. This is of
>course a boilerplate description of a typical LC circuit..... In a neon
>xformer driven tesla circuit (primary), however, I understand that the
>inductance of the neon supply xformer (its secondary winding) has a much
>greater impact on the tank circuits frequency of occilation than the
>relatively measily inductance of the tesla primary coil. Any comments?
Yes. The inductance of the neon transformer secondary has
_nothing_ to do with establishment of the RF ringing frequency of the
Tesla coil. This occurs only where XL of the primary coil matches XC of
the primary capacitor. If the secondary is also tuned to this same
frequency all will be well. If it is out, multiple RF frequencies
may be generated simultaneously and the voltage peak will not appear
at the top of the secondary but somewhere else within the secondary winding
or not at all. If the secondary is properly tuned but overcoupled, a
similar multiple frequency phenomenon occurs, often accompanied by interturn
arcing along the length of the secondary. The inductance of the neon
can and does interact with the system capacitor to effect how efficiently the
capacitor may be refilled after each firing of the oscillator spark gap. The term
(60 HZ) resonant charging comes into play here sometimes. Any
filtering chokes in series with the neon and the Tesla coil circuit
will also affect the 60 Hz charging resonance. The 60 Hz charging
efficiency of a fixed gap system can effect the number of pops you
get out of your spark gap per half cycle of the 60 Hz charging
envelope (other contributing factors here are the gap size setting and available
charging current [transformer current rating] versus cap size, etc)_rwstephens
>Second, I have heard the term "tank circuit" used to describe an LC circuit
>for years and have never found anyone who knew what "tank" orriginally
>referred to or why the circuit was blessed with this name...... it has been
>suggested that the orriginal reference may be lost in antiquity. Any
>guesses?
I will hazard to guess that in keeping with the fluid analogy often
used to describe electrical current flow, that the 'tank' circuit is
so named as that is where the energy in an electronic oscillator
circuit is stored._rwstephens
>- DavidF