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Compendium of equation used in the course and could be needed in calculations in the exam. It is hoped that we have represented all the equations here that are on the formula sheet.

Note: The sheet that you will be given is not annotated with what the equation is used for but just gives you the equation.

Note : Manipulation of the equation to find the missing item may be needed in any of the following.

The mathematical notation is being used where two letter together means multiplied

eg. P = VI is the same as P = V x I

Equation(s)

To calculate ????

Page where
equation is discussed

R(total) = R1 + R2 + R3

To find the total resistance in series Click here

To find the total resistance in parallel Click here

P = VI, V = IR

To calculate power, voltage, current, or resistance given any other two. These have been seen in the Foundation or Intermediate level courses Click here

To calculate the voltageout relative to the voltagein with regards to a potential divider where R1 and R2 represent the resistance value either side of the centre. Click here

P = V2 / R, P = I2R

As above but this set are new to the Advanced level.

Click here

To calculate the RMS of a voltage which gives the same heating effect as a direct current of the same numeric value.

Click here

To calculate the effective total capacitance of a number capacitors linked in series Click here

To calculate the effective total capacitance of capacitors linked in parallel, Click here

To calculate the value of a capacitor from area and separation of the plates, permittivity of dielectrics

Click here

To calculate the effective total inductance of a number inductors linked in series

Click here

To calculate the effective total inductance of a number inductors linked in parallel Click here

To calculate the inductive reactance for a known frequency and known inductance. Click here

To calculate the impedance from a combination of resistance and reactance. Click here

The supply voltage Vtotal (VT) is thus the sum of the vectors through the Resistor VR and Capacitor VC (or Inductor) Click here

To calculate the capacitive reactance for a known frequency and known capacitance. Click here

To calculate the frequency of resonant a tuned circuit knowing the value of the inductance and capacitance. Click here

T = 1 / f and f = 1 / T

To calculate the time period of a sine wave at a particular frequency or the frequency knowing the time period.

Click here

T=CR

To calculate the charging and discharging of a capacitor in a CR circuit

Click here

and

To calculate the Q factor ( quality Factor) knowing the value of the frequency, inductance and capacitance.

Click here

Calculation of the Q of a tuned circuit, knowing the centre frequency, and the upper and lower frequencies where the half power points are noted. Click here

To calculate the dynamic resistance RD knowing the value of the resistance, inductance and capacitance Click here

The relationship between Q and Frequency, Capacitance, and Dynamic Resistance Click here

Formulas relating transformer primary Np and secondary Ns turns to primary and secondary potential differences Vs Vp and currents Ip Is Click here

Formula relating transformer primary Np and secondary Ns turns to primary and secondary impedances Zp Zs

Click here

The two equation mean the same hfe = and is used to calculate the gain or current of a transistor. Click here

To calculate the frequency step from the crystal frequency. Click here

To calculate the out going frequency from a frequency synthesizer. Click here

c = 3 x 108 m/s

speed of light But this might be better remembered as

c = 300 x 106 m/s

Click here
The equations relating to decibel power ratios. Click here

The calculation of standing wave ratio (SWR) by reference to VFORWARD and VREVERSE Click here

v = f

c = f

Please note that sometimes v is used for the speed of light and at other times c.

From the speed of the velocity of light the wavelength can be determined knowing the frequency or the frequency knowing the wavelength. This was first introduced to you in chart form in the Foundation Licence course. Click here

The equations relating to decibel and voltage ratios. Click here

Z02 = Zin X Zout

The formula relating Z0 = the impedance of the quarter-wave length of feeder matching line to the impedance of the antenna Zin and the impedance of the antenna Zout from the matching line Click here

To calculate the field strength in volts /m given the ERP and distance from the antenna. Click here

To calculate return loss Click here

Bw is the bandwidth requirement in relation to Af is the highest modulating frequency and Δf is the carrier peak deviation frequency Click here

erp = power x gain (linear)

To calculate the Effective Radiated Power (erp) from an antenna Used in the Intermediate course

To calculate gain of Yagi over a dipole Click here



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