Author Topic: Capacitor Discharge Ignition ?  (Read 3007 times)

0 Members and 1 Guest are viewing this topic.

Offline MadMax

  • Tricycle
  • Posts: 23
  • AREA: Northeast Area
  • COG#: forum
  • Membership Level: Forum Subscriber
Re: Capacitor Discharge Ignition ?
« Reply #25 on: January 13, 2016, 06:47:37 am »
Hi Bob, The picture was very helpful. So the output transistor are 2SD1071  Specifics are: Fuji Transistor TO-220AB 450V 6A 40W. They are not even designed for ignition systems, but for high voltage audio amps. They seem to work OK though.
Now having looked at a few data sheets, it looks like the most powerful Mosfet in the same package (T0220) is the 20N50 range.  500v - 20A - 0.21Ω. That should cope with two stick coils in parallel and only 0.84v (at 4A) drop across the transistor and less internal heat.
If you just want to repair a igniter then a IRF840 (500v-8A) should be a good alternative. This is used in many ignition systems.
I wish I was at home now, I would have a go myself. But I’m on holiday until the weather warms up in the UK.  I will give it a go when I get back.
.I’ll add this to the Jobs list. I’ll also give a CDI system a go. Nothing to loose but time.

Offline Zorlac

  • Crotch Rocket
  • ****
  • Posts: 1238
  • Bulletproof, eh? I'll be the judge of that!
  • AREA: Northeast Area
  • COG#: 6962
  • Membership Level: Active
Re: Capacitor Discharge Ignition ?
« Reply #26 on: January 13, 2016, 11:26:00 am »
FWIW, power FETs may or may not be "drop in replacements" for bipolar transistors depending on the circuit.
The 2SD1071 is a bipolar darlington transistor.
« Last Edit: January 13, 2016, 01:56:21 pm by Zorlac »
COG #6962

Offline JDM

  • Street Cruiser
  • ****
  • Posts: 676
  • AREA: South Central Area
  • COG#: 8877
  • Membership Level: Asst. Area Director
Re: Capacitor Discharge Ignition ?
« Reply #27 on: January 13, 2016, 01:01:48 pm »
FWIW, power FETs may or may not be "drop in replacements" for bipolar transistors depending on the circuit.

Zorlac, good to see you are still around and kicking. Are you still running the 12v solenoid valve?
Happy New Year

Offline Zorlac

  • Crotch Rocket
  • ****
  • Posts: 1238
  • Bulletproof, eh? I'll be the judge of that!
  • AREA: Northeast Area
  • COG#: 6962
  • Membership Level: Active
Re: Capacitor Discharge Ignition ?
« Reply #28 on: January 13, 2016, 01:57:40 pm »
Are you still running the 12v solenoid valve?
Happy New Year
Yep, same to you!
COG #6962