 | Radio and Electronics (DED Philippinen, 66 p.) |
 |  | (introduction...) |
|  | 1. INTRODUCTION |
| | (introduction...) |
| | 1.1. A TRIAL TO STATE A DEFINITION OF ELECTRONICS |
| | 1.2. A SHORT HISTORY OF ELECTRONICS |
| | 1.3. CLASSIFICATION OF ELECTRONIC DEVICES |
| | 2. PRINCIPLES OF RADIO COMMUNICATION UNICATION |
| | 2.1. BASICAL IDEAS ABOUT COMMUNICATION |
| | 2.2. DEVELOPMENT OF LONG DISTANCE COMMUNICATION |
| | 2.3. FIDELITY AND DISTORTION |
| | 3. TRANSDUCERS |
| | (introduction...) |
| | 3.1. MICROPHONES |
| | 3.2. LOUDSPEAKERS |
| | 3.3. THE TELEPHON SYSTEM |
| | 3.4. PROBLEM OF FREQUENCY RANGES |
| | 3.5. BANDWIDTH |
| | 4. RADIOWAVES |
| | (introduction...) |
| | 4.1. ORIGIN OF RADIOWAVES |
| | 4.2. PARAMETERS OF ELECTROMAGNETIC WAVES |
| | 4.3. PROPAGATION OF RADIOWAVES |
| | 4.4. SPECTRUM OF RADIOWAVES AND BANDS OF RADIOWAVES |
| | 5. MODULATION OF RADIOWAVES |
| | (introduction...) |
| | 5.1. THE AMPLITUDE MODULATION (AM) |
| | 5.2. FREQUENCY MODULATION (FM) |
| | 5.3. SIDEBANDS |
| | 5.4. TRANSMISSION OF RADIOSIGNALS |
| | 6. RECEPTION OF RADIOSIGNALS (AM - TYPE) |
| | 6.1. AERIAL |
| | 6.2. THE TUNED CIRCUIT |
| | 6.3. INCIDENTAL REMARK ON BLOCK DIAGRAMS |
| | 6.4. DETECTOR OR DEMODULATOR |
| | 6.5. POWER SUPPLY |
| | 6.6. AMPLIFIER |
| | 6.7. SUPERHET RECEIVER (the SUPER) |
| | 6.8 INCIDENTAL REMARK ON MIXING FREQUENCIES |
| | 6.9. CONSTRUCTION OF A SUPERHETRADIO |
| | 7. COMPONENTS OF MODERN RADIO RECEIVERS |
| | 7.1.1. HANDLING OF ELECTRONIC COMPONENTS |
| | 7.1.2. HANDLING OF PRINTED CIRCUITS |
| | 7.1.3. DIFFERENTIATION OF COMPONENTS |
| | 8. PASSIVE COMPONENTS |
| | 8.1. RESISTORS ELECTRICAL CHARACTERISTICS |
| | 8.2. CAPACITORS |
| | 8.3. INDUCTORS |
| | 8.4. COMBINATION OF PASSIVE COMPONENTS |
| | 8.4.1. SERIES CONNECTION OF R AND C, OR R AND L |
| | 8.4.2. COMBINATION OF L AND C, RESONANT (TUNED) CIRCUITS |
| | 8.4.3. TUNED CIRCUIT CONNECTED TO AN AC-VOLTAGE |
| | (introduction...) |
| | 8.4.4.1. QUALITY OF TUNED CIRCUITS |
| | 8.4.4.2. BANDWIDTH |
| | 9. ACTIVE COMPONENTS -1- DIODES |
| | 9.1. CHARACTERISTICS OF SEMICONDUCTORS |
| | 9.2. THE PN-JUNCTION OR DIODE |
| | (introduction...) |
| | 9.2.1. PN-JUNCTION CONNECTED TO VOLTAGE |
| | 9.2.2. CHARACTERISTICS OF A PN-JUNCTION OR DIODE |
| | 9.2.3. ZENERDIODE |
| | 10. BLOCKS OF RADIOS / -1- / POWER SUPPLIES |
| | 10.1. GENERAL CONSIDERATIONS |
| | 10.2. TRANSFORMER |
| | 10.3. THE RECTIFIERS. |
| | 10.4. SMOOTHING AND FILTER CIRCUITS |
| | 10.4.1. THE RESERVOIR CAPACITOR |
| | 10.4.2. FILTER CIRCUITS |
| | 10.5. STABILIZATION |
| | 10.5.1. GENERAL REMARKS |
| | 10.5.1.1. LOAD VARIATIONS |
| | 10.5.1.2. INTERNAL RESISTANCE OF VOLTAGESOURCES |
| | 10.5.1.3. PROBLEMS CAUSED BY THE SMOOTHING CIRCUIT |
| | 10.5.5. METHODS OF STABILIZATION |
| | (introduction...) |
| | 10.5.5.1. PARALLEL-STABILIZATION |
| | 10.5.2.2. SERIES STABILIZATION |
| | 11. ACTIVE COMPONENTS -2- / TRANSISTORS |
| | 11.1. CONSTRUCTION OF A TRANSISTOR |
| | 11.2. CHARACTERISTICS OF TRANSISTORS |
| | (introduction...) |
| | 11.2.1 HANDLING OF CHARACTERISTICS OF TRANSISTORS |
| | 11.2.1.1. CONSTRUCTION OF THE STATIC-MUTUAL-CHARACTERISTICS |
| | 11.2.1.2. CONSTRUCTION OF THE DYNAMIC MUTUAL CHARACTERISTICS |
| | 11.2.1.3. CONSTRUCTION OF THE MAXIMUM-POWER-LINE |
| | 12. AMPLIFIERS |
| | (introduction...) |
| | 12.1. STRUCTURE OF A CLASS A AMPLIFIER |
| | 12.2. FUNCTION OF A SIMPLE CLASS A AMPLIFIER |
| | 12.3. ADVANCED CLASS A AMPLIFIER |
| | 12.4. STABILIZATION OF THE QUIESCENT VOLTAGE |
| | 13. CLASS B AMPLIFIERS |
| | 13.1. LIMITS OF CLASS A AMPLIFIERS |
| | 13.2. CLASS B AMPLIFIERS WITH TRANSFORMERS |
| | 13.3. CLASS B AMPLIFIERS WITHOUT TRANSFORMERS |
| | 13.4. POWER AMPLIFIER WITH COMPLIMENTARY TRANSISTORS. |
| | 14. DETECTOR OR DEMODULATOR |
| | 15. AGC-AUTOMATIC GAIN CONTROL |
| | 16. IF-AMPLIFIERS |
| | 17. FEEDBACK |
| | 18. OSCILLATORS |
| | 19. FREQUENCY CHANGERS MIXERSTAGE |
| | 20. DECOUPLING CIRCUITS |
| | 21. MATCHING OF AMPLIFIERSTAGES |
| | 22. COUPLING OF AMPLIFIERSTAGES |
| | 23. RADIO SERVICING |
| | 23.1. IMPORTANCE AND SUBJECT OF FAULT FINDING |
| | 23.2. FAULTS AND FAULT FINDING |
| | 23.3. FAULT FINDING METHODS |
| | 24. THE USE OF THE OSCILLOSCOPE |
4.1. ORIGIN OF RADIOWAVES
You know that, whenever there is a voltage between two points, an electric field is arising between these two points. You also learnt in Basic Electrical Science that whenever a capacitor is charged, one plate will be positiv and the other negativ. The consequence of these two facts is, that an electrical field, having a direction towards the positivly-charged plate, is build up between the capacitor plates as shown in figure 18 below.
fig. 18
In the same way, the voltage difference between the two wires of an aerial also generates an electric field, which has a pattern and direction that you can see in fig. 19.
fig. 19
Besides this electric field, there is also a magnetic field, which is generated by the aerial current. The plane of this magnetic field is at right angels to the direction of the current flow; and therefore is at right angles to the aerial (see below), the electrical and the magnetic fields are therefor at right angles to each other.
fig. 20
These electrical and magnetic fields alternate about the aerial-building up, reaching a peak, collapsing and building up again in the opposite direction at the same frequency as the aerial current.
In the process of building up and collapsing, a portion of these fields escape from the aerial, and become the electromagnetic waves which radiate through space, conveying the transmitted intelligence to distant receivers.
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