What Is a Transistor Radio?

A transistor radio is a radio that uses transistors to process and amplify signals. Transistor radio is simple to use and is a major broadcast receiver ^[1]

A transistor radio is a small transistor-based radio receiver. Historically, "transistor radios" specifically refer to AM radio band radios that accept mono frequencies from 540 to 1 600 kHz.

The first civilian transistor radio was developed by the Industrial Development Engineers Association of Indianapolis, Indiana, USA. At that time, the price was $ 49.95 and about 150,000 were sold. It wasn't until 1960 that as some models dropped to $ 20, transistor radios entered ordinary homes, and the influx of products from Hong Kong brought the price down to less than $ 10.

Transistor radio is the second generation radio after tube radio. with

The antenna receives the high-frequency amplitude-modulated wave (AM) signals transmitted by many broadcasting stations, selects the required radio signal through the same channel, and sends it to

1. Divided by shape and size: there are pocket radios, portable radios. Pocket green harvester can be divided into toy type, thin type and ultra-thin type. The volume of this type of transistor radio is generally between 100 and 700 cubic centimeters. Portable transistor radio can be divided into small portable, medium portable and large portable. The volume of such radios is generally between 700 and 5000 cubic centimeters.

2. Divided by use. There is a regular radio (only radio programs can be listened to). Clock radio, car radio, radio interphone, radio, radio, sing, intercom, and special information radio.

3 According to the modulation method and the number of bands: FM radio, AM radio, single-band, multi-band (also known as full-band radio, etc.).

People are used to having

To choose a transistor radio, you should first understand four basic relationships:

1. The larger the case size, the better the sound quality;

2. The larger the horn, the better the sound quality;

3 The larger the battery volume, the longer the relative service life of the battery;

4 The longer the magnetic bar, the higher the sensitivity (more closings).

Secondly, you should pay attention to five points when purchasing:

1. The change after the power supply voltage is reduced is small. When selecting, you can bring a used and used battery to replace it with a new one. The quality radio should not be affected significantly.

2. Tuning the radio station distortion is small. After finding a station, tune it to the left and right, it should have less distortion, and there should be no howling, otherwise, it means that the frequency characteristics of the intermediate frequency part are bad.

3 The volume change is small when turning the direction.

4 Small human body induction. When a person's body is close to the radio, it will have a certain effect on the radio's work, and this situation is especially obvious for short waves.

5. The noise should be small. There are two types of noise: electrical noise and mechanical noise. Turn the radio to a place without a desk, and turn the volume up to the maximum. At this time, the rustling sound is the best. Listen to a program and hear if there is noise caused by resonance of certain components when loud.

Finally, you should also pay attention to whether the tuning knobs and buttons are coordinated and effective, whether the feel is good, and whether the casing of the radio is damaged. ^[4]

1. When listening to the radio, first turn on the power switch, or turn the volume knob and hear a click, indicating that the power is on. Then, turn the volume knob to the appropriate position. Then, turn the tuning knob to find the station you want to listen to, and then turn it back and forth carefully to make the sound realistic and pleasant. To listen to shortwave or FM radio, pull out the whip antenna, close the band (or channel) switch, and carefully turn the tuning knob to tune the radio. When not listening, turn off the power switch, or turn the volume knob in the opposite direction to cut off the power.

2. The magnetic antenna in the transistor radio has a strong directivity. When receiving a remote radio station, pay attention to turning the radio to make the received signal the strongest.

3 The beam stage of the transistor radio mostly uses a Class B push-pull power amplifier circuit. The characteristic of this circuit is that the louder the sound, the more power it consumes. To prolong the life of the battery, do not announce the volume too much while listening. In addition, the volume is too high, exceeding the undistorted output power of the radio, and the sound is difficult to hear.

4 The volume of the transistor radio decreases or the sound quality deteriorates. It is likely that the battery is almost used up. Replace the new battery in time to prevent the liquid in the battery from flowing out and corroding the battery card. When replacing the battery, pay attention to the installation direction, do not fall down, so as not to damage the components.

5. When the transistor radio is not in use, keep it in a cool and ventilated place, do not expose to sunlight, do not get wet, do not shake violently, and do not listen to it outdoors in the cold winter.

6. After using a transistor radio (especially a desktop radio) for a period of time, dust can accumulate inside. Dust accumulates inside, you can open the back cover and clean it gently with a soft bristle brush. Do not wipe it with a wet cloth, otherwise the metal parts will rust. ^[5]