^^Unfortunately that is far from correct. I've gotten into many arguments about this, but if the cap/ condenser is bad or missing, the car will normally not start. So while, yes, it does keep the points from burning, it has to be in good working condition just to allow the vehicle to run. Ever look at an ignition scope pattern? The little sqiggles? That is "ringing" a term which is also applied to LC circuits (Inductor/ capacitor) circuits in RF circuits. Just like the coil magnetically charges, and then discharges, the cap ALSO charges due to the flow of current from the coil primary. These two trade energy back and forth, until "circuit losses" cause the ringing to dampen out.
In any circuit with L and C, "ringing" is THE definition of resonance, just like a bottle you blow across like a flute. If you change the value of L or C, AKA either inductance or capacitance larger, the resonant frequency is lowered. Less value of either raises resonant frequency.
Probably MUCH more important, is, in defiance of "internet wisdom," YOU CAN NOT check a capacitor with a multimeter!!!! This is because one huge problem with caps is LEAKAGE current. You MUST test caps for leakage and determine that leakage is low or unmeasurable, BEFORE you evaluate capacitance value. This is because a leaky cap, even one that is good enough that it still works -- perhaps poorly-- the leakage will cause a capacitance test to read flalsely HIGH. This means the actual capacity could have deteriorated, but the value test might read fine.
So how do you? Do what? test? Proabably cheapest and most reliable is to just replace the cap. That worked pretty well until chineseoization came along.
