Simulating an Automotive enviroment

Use an automotive spark coil driven off a relay to simulate points?

"AJ"

You can "enhance" the saw tooth ripple voltage by adding a low value resistor ( 0.1 to 1 ohm or so) in series with the filter electro. This will add a large measure of high frequency buzz to the basically 100Hz hum.

If there is not enough load current to make sufficient ripple, add a 12 volt lamp to the game.

....... Phil

Do you need this on the switched (ignition switched) or the unswitched side for product design?

If you intend to attach to the battery side, then I would suggest adding some control (a heavy switchable load would do) to simulate cranking events at least. (See ISO 7637 for details). For the switched side, you might want to add a supply interrupter for cranking events.

I won't try and suggest load dump at the moment. I agree completely with Phil on the 'normal' source.

Load dump is a whole separate matter, of course.

Cheers

PeteS

Add in a air-con magnetic clutch for lots of load dump spikes. Switch it in and out with a timer driven relay.

Thanks heaps for the replies Phil, Homer, Pete and Rob, greatly appreciated.

Regards

AJ

a LM317T wont come close to the impedance of a real automotive system.

also It'll be hard to for example simulate the spike you see on the accessory circuit when the key is turned off while the wiper or ventilation fan motor is running.

Bye. Jasen