We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
698
RADIO BROADCAST ADVERTISER
A BETTER LEAD-IN
Then this picture will tell you why you should re' fuse anything but an Electrad Certified Lead-In. Saves marring your window or door frames. Fits under locked windows. Bends to any desired shape. Imitations do that too, but they stop there. Notice what else you obtain in this Electrad Lead'In. Insulation, 10 inches long, waterproofed and protected entire length. Riveted and soldered Fahnestock clips.
Sold at all good radio stores and counters. Price 40c. Canada 60c. Ask for it by name. For safety's sake refuse imitations.
Illl
For
Clearer Purer Reception Do This
Place an Electrad Audiohm across the secondary of your audio-transformer. Then you will enjoy your radio. Kills distortion, eliminates squeals and howls. Fits all audio transformers. Easy to attach. For sale at good radio stores and counters. $1.50. Canada $2.10.
ELECTRAD
INC.
428 Broadway New York
Makers of Certified Radio Essentials and Accessories: Grid Leaks, Fixed Condensers, By-Pass Condensers, Variohms, Resistances, Rheostats and Potentiometers, Jacks, Switches, etc. Write for catalog.
FIG. 4
the dotted lines indicating that part of the former circuit which was reflexed.
It may be observed from these two circuit sketches that the audio transformer employed as the reflex agent is merely eliminated from its position and re-located as the transformer for the first straight audio amplifier. The primary
but has not the correct size, as recommended, on hand.
It is quite a simple matter to get over this, however, by the combination of a variable and a fixed condenser.
For example, suppose a condenser of .001 mfd. is desired. By shunting the usually handy .0005 variable condenser with a fixed .0005 mfd. condenser, the desired capacity is obtained.
PUSH -PULL AUDIO JMPIIMR
FIG. 5
of the push-pull input transformer, instead of being in the plate circuit of the radio frequency tube, is in the plate circuit of the new audio stage.
With the new circuit, where ux-i 12 tubes are used in the push-pull amplifier, well-nigh perfect reproduction will result, With the use of this type of tube, it is essential that 9 volts C battery be employed as a grid bias for the push-pull amplifier, with 135 volts plate potential.
CONDENSERS IN SERIES AND PARALLEL
I T IS often the case that the radio man 1 will require a condenser of a certain specified capacity when experimentally hooking up a new circuit
0005 mfd.
Max. .0005 mfd Min. .000025 »
c _^
FIG. 6
•jf Tested and approved by Radio Broadcast -fc
If, with this same variable condenser, it is desired to lower the total capacity in a circuit to which it is applied, then a condenser in series with it will produce the desired result.
In the first case — thefixed condenserin parallel arrangement — the minimum capacity that can be obtained with the plates of the variable condenser completely u n m e s h e d will be greater than when only the variable condenser alone is used, by a capacity equal to that of the fixed condenser used. If the minimum capacity of the variable condenser is. 00002 5 mfd., the total minimum capacity of the two condensers is .000025 plus .0005 mfd. See Fig. 6. If the condensers are arranged in series, as in