Can someone help me with this inductor marking scheme. They are marked using a color band system, similar to resistors. But my research turns up that they should have three bands, but all the ones I've seen have four. For example, the one I have here is Br-Gr-Br-Go. Now, my guess would be that it is 150 somethings. uH? pH? mH?
Here's the weird part. I built one of those FM transmitters, with the hand wound air core inductor, like 8 turns of #22, with 36pF in parallel, it was broadcasting somewhere in the middle of the FM band. So I pulled out that inductor and replaced it with the one I described above-- thinking maybe I could mess with the cap to get it back into the band. But when I put the new inductor in-- it broadcasted in almost the exact same spot on the band! Weird, huh? And a great signal, too! What is the deal with that?
Nother question: that capacitor across the transistor, I think someone called it a feedback cap, it's like 4.7pF. Is that value dependent on the choke and it's parallel capacitor, or is it independent?
One more thing, doing my little experiment with the capacitor and inductor in the last post, I got the value of the Br-Gr-Br-Go inductor to be about 180-220uH. Which is why I am so suprised the FM transmitter worked with it.
j.