Need help understanding how a radio works

In summary, the conversation discusses the process of using an oscillator to create a frequency and how the electric signal from a microphone is inserted into that frequency. The concept of modulation is mentioned, with the microphone altering the current to enter the oscillator circuit. A schematic is also mentioned, showing the use of a transformer or voltage-controlled oscillator for amplitude or frequency modulation, respectively. The conversation ends with a thank you and the sharing of a simplified schematic for a radio.
  • #1
x64bob
10
0
with the help of an oscillator you create a frequency but how exactly do you insert the electric signal you've gained from a microphone into that frequency?
if i understood the microphone right it transfers the vibrations into electrical form by altering let's say the current so that different amount of electrons pass trough the wire. then how do that altered current enter the oscillator circuit?
 
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  • #2
x64bob said:
if i understood the microphone right it transfers the vibrations into electrical form by altering let's say the current so that different amount of electrons pass trough the wire.

Yes.

then how do that altered current enter the oscillator circuit?

The microphone would have to be connected (electrically) to the either a preamplifier or an amplifier. So I guess the answer to the question of how the altered current enters the oscillator would be: "Through a wire". But that seems like too simple of an answer. Do you have a schematic of the system you have in mind?
 
  • #3
The concept you're looking for is called "modulation." Modulation is the technique of allowing one signal to change characteristics of another. In the case of a radio, the low-frequency audio signal is used to change either the amplitude (AM) or frequency (FM) of the carrier, which is generated by the oscillator.

Amplitude modulation can be done with nothing more than a transformer. Frequency modulation is commonly done with a voltage-controlled oscillator (VCO).

- Warren
 
  • #4
thanks for the help all.
here's the schematic of what i have in mind, would it work as a simplified schematic for a radio where the Gate current is the mic signal?
 

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1. How does a radio receive and transmit signals?

A radio uses an antenna to receive electromagnetic waves, which are then converted into electrical signals by the radio's tuner. These signals are then amplified and sent to the speaker, creating sound. To transmit signals, a radio uses a transmitter to convert electrical signals into electromagnetic waves, which are then sent out through the antenna.

2. What is the role of the tuner in a radio?

The tuner in a radio is responsible for selecting a specific frequency from the electromagnetic spectrum. This allows the radio to receive and amplify the desired signal, while filtering out any unwanted signals.

3. How does a radio amplify sound?

A radio uses a transistor or vacuum tube to amplify the electrical signals received from the tuner. These components act as switches, allowing a small amount of current to control a larger amount of current. This amplifies the signal, making it loud enough to be heard through the speaker.

4. What is the difference between AM and FM radio?

The main difference between AM (amplitude modulation) and FM (frequency modulation) radio is the way in which the signal is transmitted. AM radio transmits signals by varying the amplitude of the wave, while FM radio varies the frequency of the wave. This results in a difference in sound quality, with AM radio having more static and FM radio having clearer sound.

5. Can a radio receive signals from other countries?

Yes, a radio can receive signals from other countries as long as it is capable of tuning into the frequency of the desired station. However, the strength of the signal may be affected by factors such as distance, atmospheric conditions, and interference from other signals.

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