Hi all I have a question concerning the voltage required to initiate the ignition spark in a combustion chamber. I learnt this voltage depends on the dielectric in the plug gap. The more pressure the higher voltage, the richer gas mixture the lower voltage,....and so on....there are many variables which condition the required voltage to "trigger" the spark. Now, my doubt. I own an old 2-cylinder car (citroen 2CV) with a points ignition system without distributor and a dual output ignition coil, so that is a waste spark system. While one cylinder is compressed for ignition (useful spark), the opposite is in the exhaust stroke (waste spark). If we need, say, only 8000 volts for sparking in the exhaust cylinder, because that chamber is unpressurized. How can the coil still go up to, say 12000 volts for initiating the spark in the opposite highly pressurized chamber? It is supposed that just when a spark is stablished, the voltage falls down dramatically to that value just to maintain that igniting initiated spark, which may be between 3000 and 4000 volts. So, just when the waste spark initiates, the secondary coil voltage drops and there is no option to get the 12000 volts for generating the useful spark. What am I thinking in wrong? Any input is greatly appreciated. Thanks.