Page:February 1916 QST.djvu/10

FEBRUARY, 1916  A POETICAL ONE. Oh, Kathis Kathkan, Wireless Jap, Explanations you need certainly sure; Your education, I think, it lacks. Why should you a radio student ask: Where goes the charge in a chunk of air? The charge it stays when the metal is near; Blowing admits of no avail, But remove the plates, now where the
 * charge?

Charge has scattered far and wide Nothing to hold it; why should it stay? The more it scatters the weaker it grows, Weaker and weaker as the distance squared. Finally it vanishes and disappears. So goes the charge of a chunk of air. ANOM.

ANOTHER PRIZE WINNER, WHICH DESERVES THE REWARD.

New York, United States.

To Honorable Kathis Kathkan,

Distinguished Radio Student,

In Care of the Honorable Post Office Box 1155,

High Hyancus, Excellent Japan.

You aks know; I write tell. When charge condenser, dielectrics pressed much of electricity.

Air—glass—mica dielectrics; all same, no difference, dielectrics much pressed when charge condenser. So much sure.

Electrons one side condenser try jump other side.

Air, glass, mica, all same. Always try jump.

One side too few electrons: Then, now, other side too much. Suppose air, I have variable, I air vanish, all the some, condenser much pressed. Electrons from side with too many try hop side of too not enough.

Vanish I air quickly, I blow, charge stay, electrons try yet jump. Charge no never go. You think you not—you think just.

EDGAR FELIX,       528 Riverside Drive,   New York.

Mister Radio Secretary

The Headquarters

At Connecticut

Egyptian radio am me all same for railroad and war and me want race for Japanese ask to know condenser electricity where goes if blow its air by breath way me say yes sure away away blow but not, electricity charge of condenser dielectric all same blow no certainment not cause given good books why condenser charge he lives by the space and him is ions what you call english words so no man him blow he breath away space impossibly so all same now you send me five dollars if you please from

respectlyfull          MURAD BEY ALLID,      Egyptian Radio Operator.

Count Murad Bey Allid neglected to give his address. The Count is evidently quite a radio expert.

A SERIOUS ANSWER TO K. K.

By E. E. House, Battlecreek, Mich.

In speaking of a condenser, the dielectric is a very important factor, but no more so than the metal plates which are the other part of this instrument. Yes, under certain circumstances, the dielectric of a condenser is very hard pressed, even to the point of puncture after which a condenser is useless.

If the dielectric is glass, the pressure on the glass is equal to the applied voltage, the area of the surface receiving the charge, and the time of charging. Using 20,000 volts as a unit and applied to a small condenser, we find this voltage in the normal air pressure of 15 pounds per square inch will break down the air between two points which are the opposite sides of potential, and one inch apart.

If the 20,000 volts are applied to a small condenser, and a gap of one inch is placed across the same, we find the condenser will charge and discharge several hundred times per second. Taking the pressure from a 60 cycle or 120 frequency per second, it will discharge several times per period. Open up the gap and the discharge will be less frequent, while the condenser voltage will run up to about thirty thousand. The discharge will be prominent of the 120 frequency of the applied power. Then close gap to one-half inch and the discharge will increase to several hundred thousand and just hiss.

This condition, of changes in the discharge frequency, may be developed by changing the area of the condenser. Making the condenser large requires a longer period to charge and a less frequent discharge will be the result. It is possible to make a condenser so large that it will absorb practically all of the applied E. M. F.

The thickness of the dielectric, for a given pressure depends on its insulating quality. Mica and glass rank high, while air is low. The thickness of the dielectric also depends on the area of the condenser, the time of charging, and discharging in proportion to the applied potential. Yes, air can be used as a dielectric, but is of little value in its natural condition. By pumping air into a tank which holds the condenser plates, we can use it as a dielectric, because its insulating qualities increase with pressure. Arlington uses condensers insulated by air at 250 pounds pressure per square inch. If I am not mistaken, a potential of 18,000 volts is applied 