series resistance for relay control

Just wanted to know if it was a hybrid. On the Prius, the cut wire is constant, doesn't apply to normal gas/diesel cars. Could you show the circuit? K.P. or Oldspark might be able to comment on what's happening.

A Darlington transistor is just two transistors in series with each other. The benefit with this setup is your Beta is much higher, allowing for higher amplification. Since they are two discreet components wired in series as one circuit as long as the components are spec'd correctly the entire thing should behave like a normal transistor, but with a much higher capability. It would be beneficial to know more about the overall project and who is designing / making the parts being used. A simply switch controlled transistor should be able to instantly turn on an interrupt relay with no delays at all. What is the part number of the Darlington you used?Kevin Pierson