Vacuum tubes were also inefficient and fragile compared to transistors and had a limited lifetime.īell Laboratories demonstrated the first transistor on December 23, 1947. The need for a low voltage high current source to power the filaments of the tubes and high voltage for the anode potential typically required two batteries. Although portable vacuum tube radios were produced, they were typically bulky and heavy. A transistor is a semiconductor device that amplifies and acts as an electronic switch.īackground A seven-transistor Soviet Orljonok radio with the back open, showing parts.īefore the transistor was invented, radios used vacuum tubes. Beginning around 1980, however, cheap AM transistor radios were superseded initially by the boombox and the Sony Walkman, and later on by digitally-based devices with higher audio quality such as portable CD players, personal audio players, MP3 players and (eventually) by smartphones, many of which contain FM radios. The pocket size of transistor radios sparked a change in popular music listening habits, allowing people to listen to music anywhere they went. Billions of transistor radios are estimated to have been sold worldwide between the 1950s and 2012. Transistor radios are still commonly used as car radios. The mass-market success of the smaller and cheaper Sony TR-63, released in 1957, led to the transistor radio becoming the most popular electronic communication device of the 1960s and 1970s. Following the invention of the transistor in 1947-which revolutionized the field of consumer electronics by introducing small but powerful, convenient hand-held devices-the Regency TR-1 was released in 1954 becoming the first commercial transistor radio. Ward, see Transistor Radio (album).Ī classic Emerson transistor radio, circa 1958Ī transistor radio is a small portable radio receiver that uses transistor-based circuitry. You will hear many stations.Īdjust a core of 5.5MHz IFT coil until you hear a clear station coming out from your FM radio.So, your FM radio is working and ready for listening.This article is about an electronic device. Gently tune a VC1 trimmer capacitor or adjust a coil L1 by pulling towards. You will hear a hissing sound comming out from a speaker of an Audio amplifier. Now connect an output (2-pin connector) from your FM radio to an input of AF amplifier.Ĭonnect 4* 1.5V AA battery or 6 Volts battery to your FM radio receiver. Also connect a +6 Volts to an AF amplifier. Here i used a LM 386 AF amplifier.Ĭonnect a speaker and connect it an AF amplifier. Take a 5.5 MHz IFT coil and connect it in parallel with a resistor R1 (2K2).Now connect them to a pin 12 of IC1 and +6 Volts.įor a calibration you will need a low power Audio amplifier. Place a transistor Q1 on a left side of a zeroboard and 2-pin connector to a right side of a zero board. Now take a 18-pin IC socket and place it on a middle of a board. Now take a 5mm drill bit and gently wound 5 turns of 23 SWG copper wires. Take a piece of 23 SWG wire and remove its enamel on two ends. Don’t insert an IC on a IC socket while soldering IC socket on zero PCB.Before we construct this radio we will make a coil L1 of 5 turns of 23 SWG wire on a 5mm air core. Construction and CalibrationĪfter inserting all the components take a 25W soldering iron and solder all the components. An antenna of 75cm long wire is connected to a base of Q1 (BF494) through a capacitor C9(102). Capacitor C11 (10pF) is connected between an emitter and collector of Q1.Capacitor C10 (.01uF) is connected between base and ground.Ĭapacitor C12(33pF) is connected between an emitter of Q1 and to an input terminal of a 5.5MHz ceramic filter and to a pin 1 of IC1 (AN7223). Coil L1 is connected in parallel with a VC1 (2-22pF) and connected to + 6Volts and collector of Q1 (BF494). Resistor R (470) is connected between ground and emitter of Q1 (BF494). Resistor R2 (470K) is connected between a base of Q1 (BF494) and +6Volts. An audio output is taken out from pin 13 of AN 7223 through an electrolytic capacitor C13 (10uF/25V) from a 2-pin connector.
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