Thursday, January 23, 2014

winding coils, rfc

 Winding the RFC..

One 100 micro henry rfc was needed for VWN tx. wound it but it did not work in the tx. I was puzzled. Finally found out that the resister of 2watt was wire wound type. So it itself was an inductor. When two inductors are placed in paralled it reduces the inductance.... Thus , we need  a carbon variety here. Carbon resistors are non inductive. All quarter watt, half watt resistors are having carbon material.

I bought resistor from  shop,  he said it is carbon but on scrapping the cover, revealed contrary. Touch the resistor with nail. If there is few road bumps, it is wire wound. A quarter watt carbon resistor is used but its diameter is very small, so few rolls of paper is cut and rolled over this resister which makes it thick enough.

A thin wire removed from the CFL bulbs transformer is taken may be about 40 swg. It is really thin and brittle so easily breaking.

As shown above the choke coil is wound. For scraping the insulations one small used emery-paper is utilized. Here the torch,heat, file does not work. That finished the rfc. Measured in total 220 turns (100 plus 120) gives me inductance of 97.6 micro-henry. Mission accomplished.


Thats is folks ! wheel has been re-invented.