User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0
The diode has two functions.
1. To allow the inductive kick back from the coils to have a high
impedance ( like it would when the contacts open in a car ignition
circuit) this ensures the field collapses quickly generating the high
voltage.
2. To prevent the inductive kick (~400v -ve pulse) back flowing
back in to the 30v rated transistors releasing the magic smoke.
I do have a problem with that circuit, a 1n4007 is a 1A diode. Most
ignition coils saturate at 5-10A, so either the on time is so short as
to limit the current to 1A (with reduced output) or the diode is
severely underrated.
Derek
On 10/01/16 23:09, Ed wrote:
Answer is yes, at least in my experience, and a lot of current flows
through the diode. I forget the rules about attachments but I have a
file on the subject of ignition coils and ignition coil drivers
including schematics and pix and will send if big brother allows.
On 1/10/2016 1:49 PM, Reverend Fuzzy wrote:
I ran across this diagram for an ignition coil Driver...
[begin link]
... and was wondering what the purpose of the 1N4007 diode is. Is it
even
necessary?
---
Reverend Christopher "Fuzzy" Mayeux
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla