With more highly perfected appliances, as a vacuum, or audion tube, and an aërial elevated from sixty to over a hundred feet, you may receive radio energy thousands of miles away.
These Vesta batteries are the "A" batteries used for heating the filaments of the audion bulbs.
The improved audion holds out a wonderful future for radiotelephony.
For the receiving of messages from distant points without a conspicuous aerial an audion would have to be used and this would set up feeble oscillations which could be picked up under favorable conditions by the portable compass.
Having improved the audion and used it successfully for long-distance telephone conversation over wires, the telephone company began to experiment with wireless telephony.
The audion is a small glass bulb from which the air is exhausted to a high degree of vacuum.
Messages could be received from great distances without any extensive or elaborate aerials, and the audion could be used at the sending-station to magnify the signals transmitted and send them forth with far greater power.
Used as a relay, the improved audion made it possible to pick up very faint wireless-telegraph messages and in that way increased the range of radio outfits.
If the audion be placed in the circuit of an alternating-current generator, it will let through only the current running in one direction.
Hence the advantage of an extremely delicate instrument like the audion to amplify the signals received.
The audion had made it possible to receive radio signals on a very small aerial.
But the audion supplied a wonderfully efficient relay and one day we awoke to hear San Francisco calling, "Hello," to New York.
Illustration: Fig 85] Suppose for example that we had an audion in the receiving circuit of Fig.
Dry Battery for Use in Audion Circuits (Courtesy of National Carbon Co.
I have substituted the plate circuit of an audion for the transmitter of Fig.
Illustration: Fig 47d] That's the same sort of thing that happens in the case of the inductance and condenser in the oscillating audion circuit except for one important fact.
Now let's take a simple case of the use of an audion as an amplifier.
Illustration: Fig 54] When the key in the plate circuit of the audion at the sending station is depressed an alternating current is started.
You will notice how I have drawn them beside and below the audion characteristic.
Illustration: Fig 116] The next step is to use the audionas an amplifier of the radio-signal before its detection.
The way of producing it, which I described, is very crude and I want to tell how to make theaudion develop an alternating e.
Illustration: Fig 99] Before we return to the question of using a transformer in an audion circuit let us turn this transformer around as in Fig.
The audion characteristic tells us what is the result.
You know also how we can use the audion characteristic to tell us what sort of changes take place in the plate current when the grid voltage changes.
Then one rule for using an audion as an amplifier is this: To get the most out of an audion see that the telephone, or whatever circuit or piece of apparatus is connected to the output terminals, shall have a resistance of R{p} ohms.
I'll say this much, however, it is the vacuum or audion tube detector that gives results, and the application of a loud speaker is only possible with a vacuum or audion tube.
I want a couple of audion bulbs, and I suppose you fellows do, too.
Not as expensive as you might think, although some of the apparatus, likeaudion bulbs, certainly run into money," replied Bob.
They agreed before parting for the night that they would meet the following day after school at the radio supply store, where they could buy some audion bulbs and whatever other apparatus they might need.
The cheapest audion bulb you can buy costs about three dollars.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "audion" in a variety of sentences. We hope that you will now be able to make sentences using this word.
