Hands-on learning radio
The basis of amateur radio is electronic technology. You will be surprised to find that the relatively boring electronic circuits are incorporated into your life. Radio is very easy to learn and very interesting. You are not stupid than others.
In the school we all calculate the resistance and capacitance in series and in parallel. "How to read the radio circuit diagram" This introductory book can help you systematically learn and master the characteristics of various electronic components.
Flashlight is the simplest circuit composed of battery, light bulb and switch. Figure 1 is the circuit diagram of the flashlight, I believe you will understand at a glance. By disassembling and assembling the flashlight, you have mastered a household appliance repair technology-repair the flashlight.
Figure 2 is a typical circuit of an ore radio. Many beginners have tried to do this. This ore radio that can listen to the radio uses only four components: diodes, capacitors, coils and headphones, so it seems that it is not difficult to make radios.
Learning electronic technology can also bring economic benefits. Incandescent bulbs are relatively easy to damage. Find a diode (1N4007) and put it in series with the bulb (Figure 3). A 100W bulb in series with a diode is only equivalent to 60W bulb brightness, but it greatly extends the life of the bulb.
Transistor has a decisive position in radio technology. Figure 4 is a typical high-frequency oscillation circuit, we can use a medium-wave magnet bar coil, variable Capacitor, transistor (9014) and other components to build a test circuit. Hands-on building such a circuit can not only improve the hands-on ability, but also play a lot of tricks.
1. The medium wave wireless microphone is connected to the B and C terminals of Figure 4 with a dynamic coil microphone. The medium wave radio is adjusted to no station, the circuit of Figure 4 is close to the radio, and the variable capacitor is adjusted to make the circuit oscillation frequency and the medium wave receive Same frequency. When you sing into the microphone, the radio will find a loud sound.
2. Hearing aids Use the electret microphone shown in Figure 5 in combination with Figure 4 and cooperate with the medium wave radio to form a simple deaf hearing aid.
3. The audio signal tracer leads the wires from the B and C terminals of Figure 4 as probes to make an audio signal tracer, which can be used to repair audio circuit faults.
4. Receive campus AF broadcasts and telephone amplification. Connect a large inductance coil with an open magnetic circuit to B and C of Figure 4 (can be replaced by a black and white TV high-voltage coil), place the inductance coil in the appropriate part of the phone, and cooperate with the radio Make a phone call.
The inductance coil has high sensitivity, can pick up the weak audio magnetic field signal, and can listen to the campus AF broadcast with the medium wave radio.
Do the above experiment, I believe you will be very interested.
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