Diode am radio Also it works as an AM demodulator. Earphone or small speaker. You must be logged in to post a review. x List at least two limitations of TRF radio receivers. active-filter am-radio cascaded-filters full-wave ham-radio Precision Full-Wave Rectifier PUBLIC. It serves as a So in this tutorial we showed how to design Simple Amplitude Modulation (AM) circuit using Single Diode Modulator. Semiconductors have electrical resistivity that varies While I was bored and had nothing better to do over the course of the last weekend I came across serveral websites which outlined the history of vacuum tubes and/or electronics and they all mentioned (Flemming's) vacuum Welcome to Reddit's own amateur (ham) radio club. This helps detect VARIABLE CAPACITANCE DIODE (AM RADIO BAND TUNING APPLICATIONS) 1SV214: 111Kb / 2P: BARIABLE CAPACITANCE DIODE (TV TUNING) 1SV103: 119Kb / 2P: Variable Capacitance Diode, FM Radio Band We used Schottky diode 1N5817/5818 instead of germanium diode and successfully received radio programmes with an external antenna longer than 18 metres. 5V battery. Assembling a crystal radio is a simple and fun project that allows you to tune into AM radio stations without needing an external power source. This This one is a homemade tunnel diode. If you are wondering what Amateur Radio is about, it's basically a two way radio service where licensed operators throughout the world Here is an example of a leaky peak detector for AM demodulation: Note that I have amplified the AM signal by a factor of five in order to make the peak detector’s input signal A germanium diode (1N34A or similar) 3. Square law modulators use a nonlinear Here's a single diode AM modulator from an earlier answer of mine: - Probably the main thing you missed in your modulator was a little bit of DC biasing. The simplest AM detector is just a diode. Opens in a new window or tab. The diodes were made out of Galena Well, AM signals can be decoded by simply using a rectifier and a low pass filter. Dimensions (WHD) 14. ZR1141: Variable Capacitor: RV5728: Crystal Earpiece: AS3305: 15 to 30m Hookup Wire: WH3010: Foam-core board: NA: This version does involve a tuning capacitor, but we're The NTE618 is a silicon varactor diode with a good linearity and high capacitance ratio that is capable of being operated from a low voltage. The AM radio signal at the source flows through C3 to the base of Q2, which functions like a common-collector stage. i tried my hand NTE618 Varactor Silicon Tuning Diode for AM Radio . The diode is fundamental because it works as a simple envelope The next design is a RF (radio frequency) diode detector, you can measure the amplitude of a RF signal with it. : If you have an understanding of how AM radio work then you have a basic understanding of how radio and even TV works. 6 MHz, approximately. 15. They were made by Generall Electric. 75 inch / Understanding How AM Radios Work. It was the first method developed for making audio radio transmissions, and is still used I would not recommend itwhen building a AM radio for the first time as it will take a lot of tuning to find out whether it works or not. So in a Crystal Radio Receiver you need only to produce around . Buy it with. 99. However the 1N34A Germanium Diode actually starts to conduct at very low voltages. 5 or 1W, 8 ohm speaker: The MK484 we use is a Japanese copy of the original ZN414. Medium wave is a band of radio frequencies extending from 530kHz to 1700kHz. 816 Posts Alternator whine is caused by a small amount of AC signal component on your DC power supply to the radio. The diodes were made out of Galena There are several versions of amplitude modulators on the Net, but most are completely unsuited to running distortion tests, because the AM carrier has a significant distortion AM Detector. far superior to a germanium diode detector. Brand New. Edited June 29, 2020 . Related products. 2, Feb, 2007 Abstract is generally the result of back biasing of the detector diode [often due to Germanium Diode AM Radio LAB 3 3. This radio, as Before accessing to our website choose one of the 2 options: Swipe to Left: "Reject", DigChip will use cookies only for ensure that our services will they work properly, track outages and protect against spam, fraud and abuse. For the 60m long antenna, Getting a proper AM modulated signal requires A low cost,simple radio circuit schematic using op amp. This is due to the property of diode i. This Schottky diode has the On the image from my scope you can see the 50Hz sinusoid and other hash which I am not too concerned about as of yet, but, I would like to reduce or eliminate that huge PRUNUS J-199 Large Vintage Radio Bluetooth, AM FM Radio Shortwave, 15W Crystal Speaker, Support AUX/TF Card/USB Playing, AC Charging, Rechargeable Battery and Battery Design a parallel resonant circuit for an AM radio receiver. The schematic is shown in Figure 3. The demodulation process also produces When the radio signal is applied to the diode, only half the waveform passes through it and half of the waveform is removed. 5 out of 5 stars 46 ratings. ) The best Demodulator diode (D2 shown below) often has no DC bias. The detection of AM radio signals is a diode application. 57. This circuit takes the signal from the antenna, Look for the "BLUE" arrow - that part takes in 8 volts bias from the RX line, and shoves it into the AM detector - every radio that has an ANL/AM detector uses a Tickler as a Tunnel diodes current rating. Don't rule it out just yet. com FREE DELIVERY possible on eligible purchases In this Simple AM Radio Receiver, the variable capacitor and coil together are making the tuned circuit or the tank circuit. x Draw a block diagram of a superheterodyne In this laboratory exercise you will build a germanium diode based AM (Medium Wave) radio. 1 volt from your Crystal Radio Set VARIABLE CAPACITANCE DIODE SILICON EPITAXIAL PLANAR DIODE(AM RADIO BAND TUNING) STMicroelectronics: TDA7705: 427Kb / 42P: Highly integrated tuner for AM/FM car radio September 2013 Rev 9: TDA7706: NTE618 datasheet, NTE618 pdf, NTE618 data sheet, datasheet, data sheet, pdf, NTE Electronics, Varactor Silicon Tuning Diode for AM Radio | Home | All manufacturers | By Category | FR: The document discusses AM diode detectors. Explain how a diode AM detector works. Turns out, he’s using the diode to rectify the signal and the looooong cable works as an inductance (which The diode produces a DC component from the AM signal, with audio riding on top (added). It has two stages of pre-amplification and a Class AB power amplifier. x Draw a block diagram of a TRF radio receiver. by mk5734 | updated Important is that some electric contact (in this case in the mouth) shows semiconductor properties like a diode, some decades ago I could silently hear an AM radio station on my headphones connected to my fully turned up I wanted to build a "hi-fidelity" AM receiver and needed an ultra-linear AM detector for it. Similar Description - 1SV101: This is a "crystal radio", an AM radio receiver with no amplifier. Sponsored. Q1 is configured like a common-drain stage. 99 $ 6. by mk5734 | updated September 21, 2018. Brand: Ximimark. This low part count design was used to receive a local AM radio station at considerable volume. The circuit in the figure Stop calculating. The circuit demodulates an AM (DSBFC) signal using a diode half-wave rectifier followed by an RC circuit. For instance you can use the circuit for: As diode I am going to use the BAT62-03W. This device is intended for use in AM receiver electronic tuning applications. Here's a basic guide to help you create a basic AM radio using two transistors: Diode Clip fifty feet of wire onto a handheld AM radio and you'd be surprised. 5. org One may build an FM radio in Make a Simple AM Radio: Building a simple 2-transistor AM radio can be a fun and educational project. A Low Distortion AM Detector and AGC System By Steve Cloutier, WA1QIX Revision 2. Your run of the mill AM radio uses a ferrite rod to acheive decent reception in a "pocket size" package. Ground wire. 5” diameter coil and variable capacitor form a resonant circuit to select the frequency and a diode rectifies (demodulates) the modulated radio frequency carrier. Description: The NTE618 is a silicon varactor diode with a good linearity and high capacitance ratio that is capable of being operated from a low voltage. Usually looks like a small piece of glass with wires VARIABLE CAPACITANCE DIODE SILICON EPITAXIAL PLANAR DIODE(AM RADIO BAND TUNING) Toshiba Semiconductor: 1SV101: 150Kb / 3P: VARIABLE CAPACITANCE DIODE (FM TUNER APPLICATIONS) Siemens For reference, the AM broadcast band runs from 500KHz to 1600KHz. The raw antenna feed is shown in the first scope slot in the lower left. Earliest radios used simple diode detector circuits. The diode is fundamental because it works as a simple envelope Crystal sets receive AM (Amplitude Modulated) radio stations by using a simple demodulation scheme. Foxhole radio - Wikipedia en. Diode: in that same cannibalised radio find a small signal diode and use that. An (old) Nano to The output is monitored using an AM radio. OPamp might benefit from a negative as well as positive DC supply, since its audio AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. Fig 7. Design is visible in our gallery and to anyone with the link. 59 shipping. A typical circuit diagram for Explain the steps necessary in the reception of a radio signal. Here's what I know; Image (a) - That capacitor above the varicap isolates the tuned circuit from the DC tuning voltage, but still allows the capacitance of the varicap to 20Pcs 1N34A DO-35 germanium detector diode AM/FM crystal radio_WKXIs-'h. 7. txt) or read online for free. x x x x x Given the schematic diagram, recognize the functional blocks and signal flow The diode detector in an AM radio receiver is usually found _____ a) Before the first RF stage b) After the first RF stage c) After several stages of amplification d) None of the above AM radio broadcasting has been a popular means of communication for decades, and understanding how an AM receiver works is essential for anyone interested in electronics BARIABLE CAPACITANCE DIODE (AM RADIO BAND TUNING APPLICATIONS) 1SV103: 119Kb / 2P: Variable Capacitance Diode, FM Radio Band Tuning Applications KEC(Korea Electronics) KDV149: 270Kb / 3P: The discovery of the germanium diode during WW2 and the subsequent discovery of the point contact transistor by Bell Labs in 1947, rekindled the joys of simple receivers, as those (Please assume a diode demodulating AM radio of the most imaginable simplicity. You can make the 1:1 buffer using an NPN emitter follower. The idea of the battery is to put a DC bias on the detector diode, until it is almost conducting. The carrier frequency of 500 kHz is close to Receivers for ordinary AM and FM have, for the most part, continued to use traditional analog detectors, but receivers for the newer digital radio formats can also use their digital signal processors to demodulate Emergency Ra Di Os Ra Di O S Portable Am Fm Emergency Solar Diode Crystal Radio. The inductor could be a standard AM radio ferrite rod antenna while the tuning capacitor is a variable plastic Model: FM/AM Automatic Tuning Radio Esaki Diode AFM-152 - Sony Corporation; Tokyo; Shape; Portable set > 8 inch (also usable without mains) Dimensions (WHD) 13 x 9 x 4 inch / In this project, we will upgrade a traditional shortwave superheterodyne receiver with an Arduino base tuner. strider_mt2k says: March 5, 2010 at 7:58 pm SPLENDID! The schematic and BOM show a 200µH inductor and a trimmer capacitor 150-500pF, though these parts can be salvaged from an old AM radio, to preserve the directional nature of a tuning coil, and an adjustment knob -Next to the trimmer we'll solder the first 2n2222 transistor, and the second 2n2222 transistor at the side. However, only allowing the positive edges of the modulated signal to pass through to the audio stage will Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. There are two main types of AM signal generation circuits: square law modulators and switching modulators. It begins with an overview of diode detectors and their use in AM demodulation. $6. As a result, the BC547 transistor amplifies the weak signal. While the crystal radio part (everything left of the capacitor and diode) is fine, the rest of the schematic isn't going to be up to Find many great new & used options and get the best deals for 1n60p Germanium Detector Diode FM Am TV Radio Detection 60 Pcs L6 at the best online prices at eBay! Free shipping for Going further, the OA91 diode D1 identifies the original radio signal. This circuit is the one that I designed and made when I was a little whippersnapper. biejiao (729) Before accessing to our website choose one of the 2 options: Swipe to Left: "Reject", DigChip will use cookies only for ensure that our services will they work properly, track outages and protect against spam, fraud and abuse. On a positive half cycle of the input It is Every AM radio station transmits its signal at a given frequency, and the frequency band for AM radio stations in the United States is from 530,000 Hz to 1,710,000 Hz. In principle, a slope detector can be made not much more complex than an AM diode detector A foxhole radio is a makeshift radio that was built by soldiers in World War II for entertainment, to listen to local radio stations using amplitude modulation. Then, tightly wrap a non-metal cylinder in another thin wire to create an inductor to receive the transmissions. 5 x 5. This is known as envelope detector. It contains an Anyway, what I'm trying to do is create a simple AM receiver that simply detects if a radio station is transmitting, or not. com FREE DELIVERY possible on eligible purchases 10pcs 1N270 Germanium Diode TV FM AM Radio Detection Report an issue with this product or seller. This picks up the carrier wave shown in the middle The diode rectifies the AM radio frequency signal, leaving only the positive peaks of the carrier wave. I also purchased a little booklet they published describing them, with lots of applications. The alternator generates this AC signal as a by-product of how it Buy (Pack of 20 Pieces) Chanzon 1N34A 1N34 Schottky Diode 50mA 65V DO-35 (DO-204AH) IN34A IN34 Axial for TV FM AM Radio Detection: Schottky Diodes - Amazon. The inductance can vary to adjust the resonant frequency in order to cover the full AM broadcast band, which is from 530 to 1610 kHz. A ferrite rod or air core coil. Regency TR1: First mass produced transistor radio, 1954 . Sign up to copy. I built one around 20 years ago:-) It consisted of a hand wound coil, a glass bead diode, and a -Next to the trimmer we'll solder the first 2n2222 transistor, and the second 2n2222 transistor at the side. The diode thus "detects" the audio information, pulls it off the RF carrier Lab 3: Germanium Diode AM Radio 2 For example AM radio is 550-1600 KHz, FM radio is 88 MHz-108 MHz, TV is 52-88 MHz (channels 1-6), 174-216 MHz (channels 7-12) and 470-900 “detector” for AM radio signals. We can also design AM modulator using two diodes, four However one doesn't have to use a diode type of AM detector. zaqonown (64) 100% positive; Seller's other items Seller's other items; Contact seller; AU $71. 1 volt from your Crystal Radio Set I'd like to build a simple AM radio (so simple it will only receive a single AM channel). The modulated AM carrier wave is received by the antenna of the radio receiver and is rectified by the action of a detector VARIABLE CAPACITANCE DIODE (AM RADIO BAND TUNING APPLICATIONS) KEC(Korea Electronics) KDV149: 270Kb / 3P: VARIABLE CAPACITANCE DIODE SILICON EPITAXIAL PLANAR DIODE(AM RADIO Crystal Radio net have a basic circuit that includes a 1. This radio circuit diagram consists of a sensitive audio amplifier which receives strong signals. 20. Swipe to 1n34a germanium diode, optimized for radio frequency response1n60 diode, germanium detector diode for fm, am, tv, & radio Circuit working of alarm usimg germinium Simple Diode Detector: Operation of diode detector: The Simple Diode Detector is by far the most common device used for AM demodulation (or detection), and its operation will now be considered in detail. Here's a basic guide to help you create a basic AM radio using two transistors: Projects OP, put germanium diode between the + input and your tank circuit. Germanium is a special semiconductor material, which behaves as a rectifier, hence the earliest Operation of diode detector: The Simple Diode Detector is by far the most common device used for AM demodulation (or detection), and its operation will now be considered in detail. The modulated AM carrier wave is received by the antenna of the radio receiver and is rectified by the action of a detector diode. In an effort to When tunnel diodes first became available, many years ago, I bought a couple of TD-1 devices to play with. 6. The diode Be the first to review “(10 Pcs) 1N270 Germanium Diodes 40mA 100V DO-7 IN270 1N-270 Glass Axial GE Diodes for TV FM AM Radio Detection” Cancel reply. Sale! DIY VVC Front-End for AM Radio. Created May 15, 2020 . The Schottky en Ge diode deliver approx the A: While a silicon diode can work, a germanium diode is preferred due to its lower forward voltage drop, which is better suited for the low-voltage signals in an AM radio. All it takes is a single diode to receive AM radio. 1 Introduction In this laboratory exercise you will build a germanium diode based AM (Medium Wave) radio. (It also makes a lousy crystal radio detector, so use it in conjunction with another homemade or store-bought detector diode. On the other hand, short wave extends beyond that and up to about 30MHz. Report comment. The simulation shown is for 455 kHz, but have an The AM radio IC in to92 ‘transistor’ package mentioned is the ZN414, aka MK484, aka TA7642. As diode I am going to use the BAT62-03W. 4 Crystal Radio Circuits. I removed about half of my windings, and remeasured the inductance with an LCR meter, finding now AM radio transmitter, set to transmit at 600 kHz. Next, connect those two devices, your speaker, and The simplest radio receiver, known as a Crystal Set, consists of nothing more than a coil, tuning capacitor, diode detector, and a pair of earphones. Simple Crystal Radio; One-Transistor Amplifier/Detector; TL431 Crystal Radio Amplifier; Schottky, and even a light-emitting diode! The test setup uses an People have been making diodes since before WWII. Early crystal radios used a natural Buy (Pack of 10 Pieces) Chanzon 1N270 Germanium Diodes 40mA 100V DO-7 IN270 1N-270 Glass Axial Diodes for TV FM AM Radio Detection: Schottky Diodes - Amazon. To show the radio principle to the kids, no need for exquisite performance. -and the 5k trimmer goes into the action at the side of the second 2n2222 Make a Simple AM Radio: Building a simple 2-transistor AM radio can be a fun and educational project. [1] [2] They were first reported at the Battle of Anzio, Italy, spreading later across the VariCap_____ 60/160 AM tuning cap D1, D2, D3, D4____ 1N4148 diode IC1_____ MK484 AM radio IC TO92 Speaker_____ 0. On the circuit of Figure 6-12a, C is Model: FM-AM Clock Radio 7-Transistor 6-Diode RC-7467 - Panasonic, Matsushita, Shape; Tablemodel with Clock ((Alarm-) Clock Radio). VARIABLE CAPACITANCE DIODE (AM RADIO BAND TUNING APPLICATIONS) 1SV103: 119Kb / 2P: Variable Capacitance Diode, FM Radio Band Tuning Applications More results. I have investigated a number of bipolar transistor The next design is a RF (radio frequency) diode detector, you can measure the amplitude of a RF signal with it. Q: What is the role of the transistor in an AM radio circuit? To create a simple AM radio, start by coiling up 15-50 feet of 20-22 gauge insulated wire to create an antenna. pdf), Text File (. You're making a mountain out of bla bla bla. , AM Radio O ver the past few weeks I’ve had time to examine many dozens of diodes, mostly germanium, in my crystal radio diode collection. 20 Envelope Detector The operation of the envelope detector is as follows. Resistor The radio frequency wave sweeps over only a small section of the curved part of its current/voltage curve: The diode is most usually biased near the origin. Silicon Tuning Diode for AM Radio Description; The NTE618 is a silicon varactor diode with a good linearity and high capacitance ratio that is capable of being operated from a low voltage. 1 volt. The following is the AM modulator circuit diagram A germanium diode is used to demodulate an amplitude modulated (AM) signal. Get Fast, Free Shipping with Amazon Prime. Design a circuit with an antenna for tuning your receiver to a signal of a specific carrier radio frequency so that However the 1N34A Germanium Diode actually starts to conduct at very low voltages. A diode is the simplest example of a -n junctionp, which forms the basis of all semiconductor devices. 5 4. For those of you who would like to eliminate this mechanical component, here is a modern version of the classic detector set. If there wasn’t a diode, Traditionally, in a crystal detector radio tuned circuits, a mechanical type variable capacitor is used. The diode detector in an AM radio receiver is usually found _____ a) Before the first RF stage b) After the first RF stage c) After several stages of amplification d) None of the above. But a DC bias might Buried in the Wikipedia Article on Crystal Radio is an asseration that a cat's whisker detector is a form of Schottky Barrier Diode formed by the junction between a metal Hi! I am looking for an extremely simple schematics for an AM radio - one tranzistor. They warn that the Model: National Panasonic FM-AM 2-Band 10-Transistor 7-Diode RF-757B - Panasonic, Matsushita, Shape; Portable set > 8 inch (also usable without mains) Dimensions (WHD) 230 x 175 x The 1. An AM radio schematic is a diagram that shows the electrical components and connections in an AM radio circuit. Each component x Explain how a diode AM detector works. Report content . Medium wave and short wave were the main bro I have been trying to build an AM radio for a while now and with continued failure, I am trying different avenues. The circuit bandwidth must be at least . It doesn't need anything special but the ferrite bar, the variable capacitor and the germanium diode (although it Silicon Tuning Diode for AM Radio Description; The NTE618 is a silicon varactor diode with a good linearity and high capacitance ratio that is capable of being operated from a low voltage. Copy link . You can also try a modern schottky diode if you can't find one. wikipedia. 875 x 6. This tuner is capable of receiving shortwave broadcasts on 41m band The AM radio IC in to92 ‘transistor’ package mentioned is the ZN414, aka MK484, aka TA7642. VVC diodes have been used for tuning and bandswitching in some European TV sets and in some Japanese and European AM/FM radios The point in the AM signal cycle θ = ω c t 0 corresponds to the crossover point when v AM > V DC and the diode turns on, therefore the diode current i D > 0 becomes larger Ximimark 100Pcs 1N60P Germanium Detector Diode Small Signal Switching Diode for FM AM TV Radio Detection . ) I am assuming an alternating current sine wave is coming into a wire from the antenna? In For more crystal radio circuits, simple one-transistor radios, and more advanced low transistor count radios. Table 1 Construction of AM Radio Receiver Circuit starts with local tuning Setup, AM Radio Ferrite coil and Variable Gang Capacitor makes the Local Oscillator and Resonates with the The detection of AM radio signals is a diode application. I think ac-to-dc full-wave zener-diode AM radio demodulation PUBLIC. However, the signal is relatively insignificant. Audio amplifier should not be DC coupled from the demodulator in an AM radio. The 1N34A will start to conduct around . Here is a step-by-step guide on how to The diode demodulates the RF (radio frequency) signal by removing the carrier, leaving the meaningful AF (audio frequency) part in AC form, and this is what we need to amplify using the transistor. Having A foxhole radio is a makeshift radio that was built by soldiers in World War II for entertainment, to listen to local radio stations using amplitude modulation. In amplitude modulation, the amplitude (signal strength) of the wave is varied in Simple AM Radio Receiver This circuit is essentially an amplified crystal set. It works in the commercial AM band between 550 kHz - 1. I understand that Germanium diodes have a forward drop of In this electronics circuit tutorial, we show how to design Simple amplitude modulation circuit using Single Diode Modulator. Remixed 239 times . An antenna wire (approximately 20-50 feet long) 4. 4. You'll probably need to include a (very) small 'power amplifier' to feed the aerial, which should include a broadly tuned circuit if you need to tune the This is a regenerative AM radio which uses a BB112 varactor diode for tuning. $7. Reply. This r AM circuits - Free download as PDF File (. [1] [2] They were first reported at the Battle of Anzio, Italy, spreading later across the The diode is the simplest device that allows current in one direction. or Best Offer +$0. The output of the diode effectively rides the diodes inductance resonant frequency am radio receivers Part 3 radio receiver basics tuned radio frequency TRF receivers regenerative radio receivers superhetrodyne radio receivers fm radio The contact between two dissimilar materials at the surface of the detector's semiconducting crystal forms a crude semiconductor diode, which acts as a rectifier, conducting electric current well in only one direction and resisting on Today at 11:52:58 AM Military Amateur Radio Section This section is for posts concerning the use of military surplus radio for AM and the amateur radio bands. There are other ways to achieve high quality AM detection. The absolute maximum current quoted in GE Tunnel Diode Manual of 1961 is 5x the peak current forward, and 10x in reverse. -and the 5k trimmer goes into the action at the side of the second 2n2222 The detector can be a modern semiconductor diode, a galena crystal, or delightfully low tech. I'm not interested in listening to that station, I just want my receiver to detect the radio waves For the past few years, I've been attempting to design a very simple AM radio receiver circuit. FIGURE 3. It then provides details on diode detector basics, including a In the AM detector circuit the diode rectifies the RF carrier voltage from the last IF stage of the receiver. Swipe to I am making an AM radio with the specifications of: Part 1. The audio is then extracted from the rectified carrier wave using a simple filter and fed into If you run that through a diode detector it will pass the AC portion into your low-pass filter with a variety of distortion depending on the balance of the transmitted signal and how Introduction to AM Radio Schematics. e. This item: Generic 10pcs 1N270 Germanium Diode TV FM That schematic is a typical crystal radio, and one stage of amplification, and an odd-looking speaker network. Many of them were removed from equipment The one transistor AM radio receiver is something all whippersnappers try out when starting out on the royal road to radio building. On the circuit of Figure 6-12a, C is a small The essential components of an AM radio circuit include an antenna, tuning capacitor, inductor coil, diode, capacitors, resistors, transistor, and speaker. Added to that is some remnant radio frequency, which can be low-pass filtered out. So a radio station AM Radio Coil: LF1020: Diode of Choice, see text. Home; This mechanism is provided so as to select a perfect diode VARIABLE CAPACITANCE DIODE SILICON EPITAXIAL PLANAR DIODE(AM RADIO BAND TUNING) Siemens Semiconductor G BB914: 32Kb / 3P: Silicon Variable Capacitance Diode (For FM radio tuner with extended frequency diode and a resistor-capacitor filter as shown in Fig 7.