The values of R2/R3/C1 will change the delay between the primary voltage reaching (?)volts and Q1 cutting off, which causes a spark in the secondary.Hi, I have a question about these 'Atom' modules. On the one page shown, there are different color modules, any idea what the difference is between them? It says ignition timing, how would the schematic change for different color modules? And thank you for posting the schematic!