Hi @ all! Now that I have read this and that thread here at MT and also in other forums about “free-running diodes”, I am, to say the least, a bit confused about the operation or the necessity of free-running diodes in relay circuits. So first of all, see if I have understood what it is about: If the switching voltage falls off (e.g. from the remote output of the radio), the magnetic field collapses in the coil of the controlled relay, causing a voltage that is induced around a vi Elsewhere higher than the actual “switch voltage”. What all sources agree that this voltage peak can or should be short-circuited by suitable diode switching. But what I don’t understand now (which I have also read different statements about) is the question in which circuit the diode has to be in? Here in the forum (in the two links given above) is that the radio is protected with the free-run diode. That would be – according to my lay idea – means that the induced voltage is induced into the coil itself, because the radio is attached to it. But I’m kind of hard to imagine that the coil generates a “self-induction”. Or is that so? In another place it says that the diode protects the on-board grid, so that the diode belongs in the switched “load” circuit. That’s obvious to me in so far as I can imagine how the coil induces into the “load” conductor, but here I wonder, whether such a voltage peak does not “disappear” due to the very small amount of charge in the on-board network? If one of the people who have had the idea has had a pity to explain it to me again, I would be very grateful! Ciao & Greetings Marc