Good MMC Capacitors

Published December 26, 2013. Updated February 24, 2021.

Here is a list of capacitors tested by the high voltage community to be known to withhold the use as primary capacitor in Tesla coils.

Capacitor specifications are taken from data sheets at 100 kHz and some values for peak current, RMS current, ESR and dv/dt are estimates(* marked) from similar capacitors and graph read outs.

Product			Ipeak	Irms	ESR	dV/dT	Rth
data sheet	V	μF	A	A	mΩ	V/μS	°C/W
Aerovox RBPS20591KR6G	1000	2	854	22	7	427	15*
Kemet Arcotronics C4DRPAQ4500AA0J	1200	5	1600	64	1.1	320	3.3
CDE 942C20P15K-F	2000	0.15	432	13.5	5	2879	11
CDE 940C20P1K-F	2000	0.1	171	8.3	7	1712	11
EFD SP 2550-2	1000	3.75	2500*	152	1	810*	10*
Kemet R474N247000A1K	900	0.047	28	4*	135	600	51
Kemet R76UR3150SE30K	2000	0.15	345	10	26	2300	23
Panasonic ECWH16333	1600	0.033	198	3.5	350*	6000	40
Panasonic ECWH16473	1600	0.047	282	4.3	250*	6000	40
Panasonic ECWH16563	1600	0.056	333	5	150*	6000	40
TPC CMPPX4K0K0405	3000	4	5000	80*	0.75	1250	6.9
WIMA FKP1O131007C00	1000	0.1	1100	6	10	11000	33
WIMA FKP1T031007E00	1600	0.1	1100	6	10	11000	33
WIMA FKP1R032207F00	1250	0.22	2420	6	9	11000	33

Capacitive reactance Xc = 1 / ( 2 * π * f * C)

ESR can be calculated from the tangent of loss angle given as TANδ in the data sheets. ESR is frequency dependant. Capacitance is given in Farad, frequency in Hertz. ESR = (1 / (2 * π * f * C)) * TANδ = TANδ * Xc.

Thermal resistance (Rth) when given in data sheets are either Watt needed to raise the temperature by one Kelvin or degree Celsius the temperature raises by one Watt dissipation. Conversion from W/K to °C/W is to divide one by W/K dissipation factor.  °C/W = 1 / (W/K).

Ipeak is calculated from the dV/dT rating times the capacitance of the capacitor. Capacitance given in micro Farad times pulse rise time given in micro seconds will give a result in Ampere. Ipeak or Ipulse = C * dV/dT.

As a rule of thumb ESL is about 1.6 nH per millimeter of lead distance between the capacitor itself and the rest of the circuit. This also includes the leads of the capacitor itself. This only applies to well designed capacitors.