Impaired coupling 
of the transformer; the main inductance of the transformer is so low that the magnetising current cannot be ignored, which leads to a deviating translation ratio of the peak currents in comparison to the translation ratio of the transformer. 
Attenuation key values 
Generic term for the three characteristic variables angular eigenfrequency ωe, decay constant δ and angular resonance frequency ω0, which characterise the behaviour of the function circuit of the CD machine. 
Sweepthrough charging voltage U_{D0}/V 
is what a capacitor receives if it is charged without a freewheel circuit in the circuitry by the main current with opposite charge as the initial charging voltage. Differentiation is made between the sweepthrough charging voltage and the back charging voltage U_{Rück}. 
Electrical basic variables 
Generic term for the variables resistance, inductance and capacitance, which determine the time progression of the process variables current and capacitor voltage. 
End current I_{St}/kA 
5 % of the peak current (I_{St} = 0.05 I_{P}) on the descending path of the current curve, which determines the end of the current time t_{I}. 
Discharge time point t_{Un} 
Time point at which a capacitor that feeds the main current is discharged (uC = 0).

Fixed coupling 
of the transformer; due to the large main inductance of the transformer, the magnetising current can be ignored; the translation ratio of the peak currents and that of the transformer concur. 
Function circuit 
as part of the power circuit of a CD machine, encompasses the primary and secondary circuit, as well as the transformer. 
Joining energy E_{F} 
Energy fed directly to the joining point. 
gKE 
“Clocked capacitor discharge”; the discharge of a capacitor does not take place continuously via a switching thyristor, but rather in a clocked manner via a power semiconductor that can be switched off (IGBT). 
Halfvalue current I_{h} 
Half value of the peak current (I_{h} = 0.05 I_{P}) on the descending path of the current curve, which determines the end of the welding time t_{h}. 
Main phase (HP) 
Phase einer KESchweißung, in der der Hauptstrom den Kondensator entlädt. 
Commutation (KV) 
Phase of CD welding, in which the main current from one semiconductor valve (the thyristor) changes to another (the freewheeling diode). 
KShW 
“Shortterm welding with high heat flux density” is the process designation that consolidates resistance pressure welding and metal vapour pressure welding. The process is characterised by a high energy density, which is fed to the joining point within a very short time. 
MCS 
“Multi Capacitor Source”; technical system that uses multiple capacitors with difference capacitances for one CD welding process. 
Metal vapour
pressure welding 
Process whereby the current density in the joining point must be sufficiently large that metal vapour forms, which activates the surfaces of the joining partners. A large force presses these together to interatomic distance, whereby a bond is created through atomic attraction. A partial melt (focus) does not (generally) occur. 
Nominal basic variables 
Electrical basic variables pertaining to nominal conditions.

Back charging
voltage U_{Rück}/V 
is what a capacitor receives if it is charged by the subsiding partial current of the thyristor branch during commutation with opposite charge as the initial charging voltage. Differentiation is made here between the back charging voltage and sweepthrough charging voltage U_{D0}. 
Key parameters 
A group of individual parameters  current increase time t_{P}, peak current I_{P}, welding time t_{h}, current flow time tI, capacitor discharge time tUn, currenttime integral Q_{it}, specific joining energy ϵ_{F} and effective current I_{eff }– which characterise the characteristic operating points of the CD welding process in its electrical behaviour. For a current progression without freewheel, it is necessary to add the current flow duration of the first half period t_{iπ}. 
Welding start t_{0}/ms 
the time point at which the welding process begins. According to DVS bulletin sheet 2911, this moment is marked by an exceeding of the trigger threshold (≤ 5 % of the measuring range end value) or by a specially defined parameter (e.g. the first time the transformer secondary voltage of 4 V is exceeded). 
Specific
joining energy ϵ_{F} 
The joining energy pertaining to a resistance of 1 mΩ. Additionally, ϵ_{50} is defined as the joining energy pertaining to a resistance of 50 μΩ.

Peak current ratio I_{DP}/I_{P} 
as a relationship of the peak currents of the second and first halfwave of damped oscillation without equal directionality. 
Current runon (NL) 
Phase of CD welding, in which the main current is fed from the freewheeling branch. 
Thermal coupling 
for multiphase welding. The temperature of the joining point only drops until the welding process is continued with a new pulse. For this purpose, the current must not fall below the lower limit of i > 0.3 I_{P}. 
Typifying 
of CD machines; representation of the electrical type in the form Q_{1itvIP}; whereby the two type parameters currenttime integral and current increase speed characterise the welding behaviour of the machine. Types can also be determined for multicapacitor welding. 
Recharge ratio V_{UU} 
Ratio of the sweepthrough charging voltage to the initial charging voltage of a capacitor with operation without the freewheeling branch. 
“Virtual inductance” 
A clocked IGBT as a circuit element in the function circuit, which can be used via different duty cycles like variable inductance. 
Resistance pressure welding 
Process whereby the joining point is conductively melted and the connection between the partners is established through the solidified melt (referred to as focus). During the welding process, the joining parts are pressed together under great force. 