*a* |
Coil radius |

*a* |
Coil winding height |

*a* |
N_{2}/N_{1} |

*A* |
Area |

*A*_{c} |
Core area |

*A*_{n} |
Ripple amplitude |

*b* |
Winding traverse |

*B* |
X_{c}/R_{1} at frequency f_{r} |

*B* |
Core flux density |

*B*_{m}, *B*_{max} |
Maximum operating flux density |

*B*_{r} |
Residual flux density |

*c* |
Insulation thickness |

*c* |
Specific heat |

*C* |
Capacitance |

*C*_{1}, *C*_{p} |
Primary capacitance |

*C*_{2}, *C*_{s} |
Secondary capacitance |

*C*_{e} |
Effective capacitance |

*C*_{g} |
Capacitance of winding to ground |

*C*_{w} |
Capacitance across winding |

*d* |
Core tongue width |

*d* |
Toroid diameter |

*D* |
Winding height |

*D* |
X_{c}/R_{2} at frequency f_{r} |

*e* |
Voltage (instantaneous value) |

*e*_{g} |
Alternating grid voltage |

*e*_{p} |
Alternating plate voltage |

*E* |
Emissivity |

*E* |
Voltage (effective value) |

*E*_{B} |
Plate voltage |

*E*_{0} |
Output voltage |

*E*_{1} |
Primary voltage |

*E*_{2} |
Secondary voltage |

*E*_{S} |
Secondary no-load voltage |

*E*_{L} |
Secondary full-load voltage |

*E*_{pk} |
Peak value of alternating voltage |

*E*_{dc} |
D-c voltage |

*E*_{a} |
Voltage at top of pulse |

*f* |
Frequency |

*f*_{m} |
Midband frequency |

*f*_{r} |
Resonance frequency |

*f*_{c} |
Cut-off frequency |

*f( )* |
Function of |

*F* |
Factor |

*g*_{m} |
Mutual conductance |

*G* |
Gap loss constant |

*H* |
Magnetizing force |

*H*_{c} |
Coercive force |

*i* |
Current (instantaneous value) |

*I, *|*I*|*, I*_{rms} |
Current (effective value) |

*I*_{dc} |
Direct component of current |

*I*_{pk} |
Peak value of current |

*I*_{av} |
Average value of current |

*I*_{p}, I_{b} |
Plate current (d-c) |

*I*_{L} |
Load current |

*I*_{E} |
Loss component of exciting current |

*I*_{M} |
Magnetizing current |

*I*_{N} |
Exciting current |

*I*_{G} |
Grid current (d-c) |

*j* |
sqrt(-1) (vector operator) |

*J* |
Low-frequency permeability/pulse permeability |

*k* |
Thermal conductivity |

*k* |
Coefficient of coupling |

*k* |
1/2 ratio of impedance/circuit resistance = sqrt(L/C)/2R |

*K* |
Constant |

*l*_{c} |
Mean length of core (or magnetic path) |

*l*_{g} |
Air gap |

*L* |
Inductance |

*L*_{e} |
Open-circuit inductance (OCL). |

*L*_{s} |
Short-circuit inductance |

*L*_{m} |
Mutual inductance |

*m* |
Decrement |

*m* |
Order of harmonic |

*M* |
Modulation factor |

*MT* |
Mean turn length |

*n* |
Number (e.g., of anodes) |

*N* |
Turns |

*N*_{1} |
Primary turns |

*N*_{2} |
Secondary turns |

*N*_{L} |
Number of layers (of wire in coil) |

*OCL* |
Open-circuit inductance |

*p* |
Density |

*p* |
Ratio of voltages (in autotransformer) |

*p* |
Rectifier ripple frequency/line frequency (number of phases) |

*P*_{a} |
Volt-amperes per pound |

*P*_{c} |
Core loss |

*P*_{A} |
Ripple amplitude/E_{dc} (in rectifier) |

*P*_{R} |
Ripple amplitude/E_{dc} (across load) |

*PFN* |
Pulse forming network |

*PRF* |
Pulse repetition frequency |

*Q* |
ωL/R = coil reactance/coil a-c resistance |

*r* |
Radius |

*r*_{e} |
Equivalent radius |

*r*_{p} |
Plate resistance |

*R* |
Resistance |

*R*_{1} |
Source resistance |

*R*_{2} |
Load resistance |

*R*_{L} |
Load resistance |

*R*_{e} |
Equivalent core-loss (shunt) resistance |

*S* |
Secondary winding |

*S* |
Core window width |

*t* |
Time (independent variable) |

*t* |
Thickness of insulation |

*T* |
Period of a wave |

*T* |
2πsqrt(L_{s}C_{2}) (undamped period of oscillatory wave) |

*V* |
Commutation voltage |

*V* |
Volume (of core) |

*w* |
Core-stacking dimension |

*W*_{g} |
Gap loss |

*W*_{e} |
Core loss |

*W*_{s} |
* *copper loss |

*X* |
Reactance |

*X*_{N} |
Open-circuit reactance = 2πfL_{e} |

*X*_{C} |
* *Capacitive reactance = 1/(2πfC) |

*X*_{I} |
* *Inductive reactance = 2πfL |

*Z* |
Impedance |

*Z*_{G} |
Source impedance |

*Z*_{L}, |
Load impedance |

*Z*_{0} |
* *Characteristic impedance |

*α* |
Amplifier gain |

*α* |
sqrt(C_{g}C_{w}) |

*α* |
Damping factor |

*ω* |
Feedback constant |

*ω* |
Natural angular frequency |

*δ* |
Small interval of time |

*Δ* |
Increment (e.g., of flux) |

*Δ* |
Exciting current/load current |

*ε* |
Base of natural logarithms (= 2.718) |

*ε* |
Dielectric constant of insulation |

*η* |
Efficiency |

*θ* |
* *Temperature |

*θ* |
* *Phase angle |

*μ* |
* *Amplification factor |

*μ* |
Permeability |

*μ*_{Δ} |
Incremental permeability |

*π* |
3.14159 |

*φ* |
* *Phase angle |

*φ* |
* *Flux (varying) |

*φ*_{max} |
Peak value of flux |

*Σ* |
Summation (of a series of elements) |

*τ* |
Pulse duration |

*ω* |
2πf (angular frequency) |