Try This

Radio Record, Volume V, Issue 5, 14 August 1931, Page 30

Try This

8 we have now very nearly come to the end of all the parts we can use in a radio set, let us have a little revision. Take a pencil and paper and see if you can draw the theoretical circuit for the following :- A erystal, aerial connected to the top o£ a coil, the bottom of which is connected to earth. Now indicate an "A" battery, show the two poles joined to either end of a fixed resistance. Draw a three electrode valve with a potentiometer across the filament. Take the centre tap to earth. Now turn back to the last two or three weeks of the "Radio Record" and you will see if you are right. Once we have completed the various parts of the set we shall go on to talk about how radio circuits are built up, and before long you will be drawing and understanding the different types of circuits used in radio work. You will find that you will naturally look at the theoretical circuit and not at the lay-out when you come to decide whether a set is good or not. Next week, too, we hope to deal with a few questions that were raised by one correspondent. He- found that after Yeading the "Diagnosis" he could go through his set and understand how everything was working until he came to the first audio transformer and found that it behaved in a manner in which it should not behave. But really, it is behaving correctly. We wonder if before next week he will be able to think out exactly what happens.