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NE555P Timer IC

Here I discuss again the continuation of CDI Ignition  Schematic with NE555. Previously I would like to remind, I making a series of experiments has been more than two years ago. Please check the date of my first post 🙂 It’s updated now, but the first post still years ago.

And as such, and because I was quite busy recently, I couldn’t conduct further tests on this circuit. So,  I just give  some ideas or designs. If you want to make it please expand your creativity with my schematic circuit as base . First, if you haven’t seen my first series of CDI Circuit Schematic Diagram with NE555, please check the link How to Make Your Own CDI Box with cheap NE555 .

Multispark Trigger CDI Circuit Schematic


NE555 Multispark Trigger Circuit

 

Here I only give circuit schematic of triggering circuit for new version only. For other schematic model, please check How to Make Your Own CDI Box with cheap NE555 . Another schematic  part of this CDI model still the same as the first version.

The above is a CDI schematic of trigger circuit multispark version, meaning that this circuit will issue some spark (fire) in a row at a time when CDI triggered by the pulser signal.
Please refer to the following illustration of the oscilloscope:

 

From that picture can be seen each sparks consist of several successive spark at once that happened very quickly. In theory, this way, will lead to sparks of longer and larger sparks. The amount of this spark will decrease if the rpm higher . So CDI will continue to function well at high rpm, while at low rpm will be more perfect in combustion, which means that gasoline will be more efficient.

The following illustration are the results of measurements made by John Clarke

The problems that arise from this CDI Iginition

The cdi box originally supposed to use dual transistor or fet working in pairs (in electronics so-called push-pull). But as I discussed earlier , I couldn’t get the IC so I use NE555, of course with limitations that NE555 IC had.

By using the NE555 IC, then I couldn’t use  push pull circuit. Therefore, I modified the circuit to single spark (one spark).
However, if you really want to advance your creativity to make it go ahead.

Based on the first test I did, the result of combustion performance is not so good. It seems bigger fire, but the timing seemed not right. As a result, when the rpm rises, the engine sparks not so good. But just for note, at that time I didn’t set up the carburetor.

My analysis at that time was because the switches are still using SCR, and also not using push-pull. The nature of the SCR will continue on after triggered until the Anode-Cathode flow out, this will lead to lag or delay until the flow is completely discharged and then charged again. SCR Consequently late work (to switch) when multispark sparks and precise timing becomes chaotic.

To fix this I tried to replace it using a FET, and I’ll discuss in the next CDI circuit schematic diagaram using FET 🙂