Quote:
Originally Posted by Neil Purling
Are you thinking of the Japanese Toko coils, or has that company ceased making them?
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Toko RCL is just one of the many manufacturers of these coils. They are usually very good quality. Most now come out of China. For many years Jaycar sold a coil kit with the Red slug osc coil and three IF coils white, yellow & black and the small V/C and ferrite rod & coil to make AM radios.
Now though with the plethora of these coils about, there are variations of the red slug ones that look the same but are not.
Generally they all have the 5 pins. The tuned winding is the same and the tap on that is normally, for all of them, in the same place closer to one end of the tuned coil. However, the phase of the other coil (connected to the other two pins )is reversed. So if you drop these versions into a pre-existing pcb that was not designed for that, the L/O will not oscillate. But they work fine if you reverse the connections.
I don't know what proportions or numbers of the coils out there are like this. All I know is when I bought a range of these from different sellers, some were reversed compared to others, which is a real trap. One of the phasings is probably a common sort, the other may be rarer, but they are still out there.