Electronics Related Items

• c = 1.0167 ns/ft
• c = 3.33564 ns/m
• c = 299792458 m/s
• 1 Tesla = 1E4 Gauss
• .375" for BNC (3/8")
• 262' to patch rack
• 2" and 5" bends for cable
• (circular mils)*PI/4 = (square mils)
• 535MCM = 0.42in**2
• power in three phase is Watts = (average V) * (average I) * 1.732 * (power factor) ---- "average" is the average of what is measured on each phase
  

Relay rack spacing is in terms of 1.75 inch units. Hole spacing is 5/8 inch, 5/8 inch and 1/2 inch. From the edge of the "unit" come down 1/4 inch to the first hole ( holes are tapped for 10-32 screws ). The second hole down is 5/8 inch below the first. The third hole is 5/8 inch below the second. The bottom edge of the "unit" is 1/4 inch below the third hole.

Reflection Coefficient ( resistive load and ideal transmission line )
     ( Rload - Rcharacteristic) ÷ ( Rload + Rcharacteristic )

Assuming refractive index is not complex
Skin Depth for good conductors = ( 2 ÷ ( 2 × PI × ƒ × µ × conductivity ))**½
ƒ = frequency
µ = relative permeability
Loss = Absorbtion + Reflection + Correction for multiple reflections
1/e ~= 0.37
A = 8.69 * (thickness/skin depth)
A = 20 * (thickness/skin depth) * LOG(e) dB
A = 3.34 * (thickness) * (((frequency) * (permeability relative to copper) * (conductivity relative to copper))**0.5)
R = 168 + 10 * LOG((conductivity relative to copper) / (frequency) * (permeability relative to copper)) dB

50 ohm passive splitter

Total number of ports = N ( total number of inputs/outputs ).
We want to see Z ohms looking into any port.
We need one resistor, R, on each port for impedance match.
This leads to Z = R + ((Z+R)/(N-1))
which leads to R = (Z*(N-2)/N)

For Z = 50 ohms and N = 3
( to split a pulse in two )
R = 16.67 ohms

The signal amplitude is reduced to Vout = Vin*(Z/(Z+(R*N)))
For Z = 50 ohms and N = 3
Vout = Vin*0.5