Re: srsg behaviour - microsim

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 >
 > Original poster: "Jeremy Scott by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>
 >
 > What if the circuit I'm simulating has no
 > 'ground'

You must add one in the simulation, otherwise the simulator don't have
how to determine what is the voltage (in relation to ground) of the
floating parts, and can't solve the circuit.

 > (For example, the primary tank circuit
 > and power supply of a tesla coil.)
 >
 > I thought I could get away with placing
 > a VAC symbol, 15,000V, 60Hz, a coil, a
 > capacitor and a voltage controlled switch.

A ground must exist.

 > Since I now need a ground, do I have to go all the way
 > and simulate the NST to include a center tapped
 > secondary with the center tap being an earth ground?

Put two opposite VACs, simulating the two outputs of the NST,
with their connection grounded. For more realistic simulation,
split the inductance of the NST in two too, half in series
with each voltage source. If you just want to see the
waveforms, just add a ground at one side of your present
voltage source, and remember that the simulator is computing
the whole voltage across the NST, as if you were using a NST
with single output, grounded at one side.

 > PS what's the difference between Earth and Analog
 > grounds?

Nothing special. In a simulator, both mean a reference point from
where voltages are measured. In practical circuit construction,
the Earth is a real connection to Earth, and the analog ground is
the grounding point for low-level analog signals, usually separated
from other, more noisy, grounds in the circuit, not necessarily
connected to Earth.

Antonio Carlos M. de Queiroz