FORMULAE

To: tesla-at-poodle.pupman-dot-com
Subject: FORMULAE
From: "Edward V. Phillips" <ed-at-alumni.caltech.edu>
Date: Tue, 28 Jan 1997 19:31:39 -0800 (PST)
Subscriber: ed-at-alumni.caltech.edu Tue Jan 28 23:09:40 1997
Chip:
	Here are a couple of things which might interest some of the
guys. 

Ed

SOME MISCELLANEOUS STUFF WHICH MAY INTEREST SOME

TO CALCULATE Q OF A COIL FROM OBSERVED TRANSIENT VOLTAGE DECAY:

OBSERVE PEAK VOLTAGE AT TIME ZERO (Vo, AND AFTER N CYCLES Vn).

THEN

Q = 1.364 * N / LOG(Vo/Vn)

 [LOG IS TO THE BASE 10]



TO CALCULATE DISTRIBUTED CAPACITANCE OF A COIL:
DIA = DIAMETER IN INCHES
R=DIA/2
LE = LENGTH IN INCHES
V=LE/R
THEN:
CD = 5.08*R*(.0563*V+.08+.38*SQR(1/V)) 'uufd

HERE'S A COMPLETE QUICKBASIC PROGRAM TO CALCULATE SRF OF COILS:

'THIS IS SRF-X, WRITTEN 3/30/95
DIM W(40,40)
PI=3.1415927#
CLS
GOSUB 6000
BE:
PRINT "TO DETERMINE COIL INDUCTANCE AND RESONANT FREQUENCY"
INPUT "DIAMETER (in)";DIA
R=DIA/2
INPUT "LENGTH (in)";LE
V=LE/R
INPUT "WIRE SIZE";WS
INPUT "TOTAL TURNS?";NT
INPUT "ADDED CAPACITANCE (uufd)";CX
'PRINT W(1,WS)
'NT=LE*WF/W(1,WS)
IND=DIA^2*NT^2/(18*DIA+40*LE)    'uH
CD = 5.08*R*(.0563*V+.08+.38*SQR(1/V)) 'uufd. DIMENSIONS IN INCHES
C=CD+CX
FR=1/(2*PI*SQR(IND*C)*1E-09)
PRINT "TURNS ="NT
PRINT "INDUCTANCE ="IND
PRINT "TOTAL CAPACITANCE ="CD
PRINT "RESONANT FREQUENCY ="FR
INPUT "<> TO CONTINUE";CT
CLS
GOTO BE


6000 'WIRE TABLES
6020 'PRINT "     LOADING WIRE  TABLES"
6030 FOR X=10 TO 40
6040 'PRINT "" 536,X
6050 FOR Y=1 TO 3   'DIAMETER (in), OHMS/1000 ft, #/1000 ft
6060 READ W(Y,X)
6070 NEXT Y
6080 NEXT X
6090 ' THIS  TABLE GIVES, FOR WIRE SIZES FROM 10 TO 40, THE
6100 ' DIAMETER AND THE RESISTANCE AND WEIGHT PER 1000 FEET.
6110 DATA .104,.9989,31.8
6111 DATA .0927,1.26,25.25
6112 DATA .0828,1.588,20.05
6113 DATA .074,2.003,15.90
6114 DATA .0661,2.525,12.60
6115 DATA .0591,3.184,10
6116 DATA .0528,4.016,7.93
6117 DATA .0471,5.064,6.275
6118 DATA .0421,6.385,4.980
6119 DATA .0377,8.051,3.955
6120 DATA .0338,10.15,3.135
6121 DATA .0302,12.8,2.490
6122 DATA .027,16.14,1.970
6123 DATA .0241,20.36,1.565
6124 DATA .0215,25.67,1.245
6125 DATA .0192,32.37,.988
6126 DATA .0171,40.81,.7845
6127 DATA .0153,51.47,.6220
6128 DATA .0136,64.9,.4940
6129 DATA .0122,81.83,.3915
6130 DATA .0108,103.2,.3105
6131 DATA .0097,130.1,.2465
6132 DATA .0087,164.1,.1960
6133 DATA .0077,206.9,.1550
6134 DATA .0069,260.9,.1230
6135 DATA .0062,329,.0980
6136 DATA .0055,414.8,.0776
6137 DATA .0049,532.1,.0616
6138 DATA .0044,659.6,.0488
6139 DATA .0039,831.8,.0387
6140 DATA .0035,1049,.0307
6150 W(1,0)=1E-08
6160 RETURN
INPUT "WIRE SIZE";WS
FOR X=1 TO 3
PRINT W(X,WS),
NEXT X
INPUT "CONTINUE";CT
GOTO BE

SHOULD WORK IN ANY BASIC, I THINK.