Top Circuits Page 33
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Based on the classic Baxendall tone control circuit, this provides a maximum cut and boost of around 10dB at 10K and 50Hz. The first BC109C transistor (left hand side) is acting as a buffer. It provides the circuit with a high input impedance, around 250k....
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Simple add-on module. A simple approach to this problem can be done inserting a circuit in the preamplifier stage, capable of varying automatically the frequency response of the entire audio chain in respect to the position of the control knob, in order to....
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The circuit diagram of the filter section is shown in Figure 1. It is a completely conventional filter, and the component designations are the same as for the 24dB unit described in Project 09. It is designed primarily for 2-way electronically crossed over....
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The purpose is supposedly to account for the fact that human hearing is less sensitive at low and high frequencies than in the upper midrange, and that this variation is dependent upon the sound intensity (SPL). The Fletcher-Munson curve (as it is commonly....
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This simple tone control can be used in may audio applications. It can be added to amplifers, used as a stand alone control module, or even built into new and exciting instruments. It's one IC construction makes it a very compact circuit, as only a few....
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Based on the classic Baxendall tone control circuit, this provides a maximum cut and boost of around 10dB at 10KHz and 50Hz. As the controls are passive, the first transistor, Q1, is configured as common-collector to act as a buffer stage. The last....
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Circuit of a digital volume control using six discrete ICs, including a 5V regulator, is presented. IC1 (555) is configured to function as astable flip-flop. Its frequency or period may be adjusted by proper choice of resistors R44, R45 and capacitor C6....
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This digital volume control has no pot to wear out and introduces almost no noise in the circuit. Instead, the volume is controlled by pressing UP and DOWN buttons. This simple circuit would be a great touch to any home audio project...
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The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of....
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PT2350 is a tone control subwoofer cross-over low pass filter chip utilizing CMOS Technology. It features a tone control range of + 10dB (50Hz, 4 KHz) and subwoofer low pass filter of the second order Sallen Key Design. The roll-off point can be adjusted by....
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The traditional potentiometer is implemented with an electrical contact that slides over a resistive layer. An example of a well-known audio-grade potmeter is the Alps Blue. I still use this one myself. A high-end (good and costly) alternative is the rotary....
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A circuit that tailors the low end of particular items such as the bass drum and bass guitar to be used for individual tracks during mixdown, not across the entire mix. With the circuit, I can set the low end rolloff characteristic and stored energy of each....
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You'll find here few ASCII schematics for Heath and Marantz tube crossovers. They were given in L'Audiophile No 11 old sery July 1979. In the same paper there is another tube crossover designed by Gerard Chretien now at the head of Focal i'll try to....
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e circuit, is a classic circuit of electronic crossover. Stand in for, the circuits of passive crossover that exist in all loudspeaker three way. The difference is in that, it should anymore we use for each loudspeaker a separate final amplifier. Thus for....
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It many times happens, we want erase or decrease in a musical song, the voice of singer or some other sound that usually is written in same level and in the two channels. If we remove between them two signals of channels, we can take in the output a mono....
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Circuit with electronic symmetrical input, with possibility of regulation of the gain from the pontesometer RV1 and the level of signal with the RV2. The quality of pontesometer RV1 (as other material), should be very good, in order to we avoid annoying....
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This circuit could be used for replacing your manual volume control in a stereo amplifier. In this circuit, push-to-on switch S1 controls the forward (volume increase) operation of both channels while a similar switch S2 controls reverse (volume decrease)....
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Switch S2 is used for increasing and switch S3 is used for decreasing the volume. Similarly, switches S4 and S5 are provided for second channel (right channel) volume control. Also, pin 14 of IC2 can be connected to IC 74193 pin 14 (clear input) of the right....
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Electronic potentiometer using a standard CMOS logic and analog multiplexers. Pot have low distortion (0.005% less at 1 V rms) and is it easy for beginers to Understanding. In the beginning the art Hi-Fi when in the absence of high-quality potentiometers for....
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An audio source, like a mixer, preamp, EQ, or a recorder, is fed to the input of the Electronic Crossover Circuit. This signal is either AC or coupling, depending on the setting of switch 51, the non-inverting input of buffer amplifier Ul-a, a section of a....
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This article is an attenuated tone control circuit diagram. This circuit is mainly composed of transistors and RC networks are network components. As shown..
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FIG is a decay feedback tone control circuit. In the tone control circuit both have anti-attenuation Fed action. So high, in the end it is to enhance or attenuate the bass, and..
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Electronic bass equalizer type of two quad op amp circuit, you can use TL084 high-speed operational amplifier circuit shown in Figure 9-680 left and right channels through R1, ..
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The circuit of preamplifier use the 5533 chip and features a combination of controls balance and volume. Due to the nonlinearity of the human auditory system, low frequencies must be boosted at low listening levels.
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A balanced output mentioned, people tend to immediately think of the positive phase amplifier output terminal increases 0P amplifier as the inverting amplifier circuit, normal ..
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As shown, the upper and lower symmetric configuration two basic differential amplifier, differential input + IN and -IN are respectively connected cares balanced input. Because..
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As shown, there are two corner frequency: Start frequency attenuation transition of several children F 1/27rC3 (Ri + R2); by the decay into a flat corner frequency, LI. l/2rTC3..
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At high frequencies, q, Cz can be seen as a short circuit (i.e. RPi not present), as shown in Figure 4-6 (a) in the apparatus shown in FIG equivalent to 4-6 (b). Then there are..
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Bass player with a stereo control as shown by LM1877 amplifier circuit configured. Cermet stereo microphone pickup stereo turntable on the left and right channel audio signals ..
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Circuit principle: the input signal via IC1-1, and external components of the fourth-order low-pass filter to vary the slope of 24db/oct low-pass processing (figure value fc 70..
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Circuit shown in Figure 1-560 RPi is treble control potentiometer. Because C3, C4 is larger than cl, C2 capacity, so high-frequency signals, Pat, C4 can be regarded as a short ..
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Common diode balanced modulator circuit is shown. It consists of two identical performance diodes and a center-tapped transformer T composition. Diodes VD1, VD2 are 2AP9. Other..
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Figure 4-7 pitch analysis using the relation obtained above design calculation control circuit, where Ai is a buffer to put the big stage, to reduce the burden preamp output. L..
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4 ~ 20mA constituted by a TMP35 temperature transmitter circuit as shown in FIG. This circuit can be a voltage signal TMP35 output is converted into a standard 4 ~ 20mA current..
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The unit described here is simple to build, and can be quite small. The picture below shows the prototype, in a box 175mm wide, 210mm deep and 55mm high. The single circuit board is 140 x 90mm, so there's plenty of room inside for another board (a local....
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In this project, you will make a simple 3-stage low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator with amplifier. You can connect the circuit to the an electred microphone or amplified....
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In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator. You can connect the circuit to the an electrec microphone (pointed out in gray on the diagram)....
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In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator. You can connect the circuit to the an amplified microphone (no amplified microphone has a to....
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CW is the simplest form of modulation. The output of the transmitter is switched on and off, typically to form the characters of the Morse code.
CW transmitters are simple and inexpensive, and the transmitted CW signal doesn`t occupy much frequency space....
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The transmitter for the wireless headphones is built around a CD4046 CMOS phase-locked loop, coupled with a driver transistor, and a pair of infrared LEDs. ..
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IR detector diode D1 intercepts the IR signal at around 40 kHz and feeds it from U1, a high-gain preamp, to PLL, U2, a 4046 configured to serve as an FM detector. U3 is an audio amplifier that feeds a pair of headphones or a speaker...
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This stereo encoder is the perfect solution for those looking for a high quality stereo sound transmission at a low cost. This stereo encoder produces an excellent crystal clear stereo sound and very good channel separation that can match with many more....
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For the regulation it needs a voltmeter (with needle better) and charge 50W/5W. Connect charge 50W in the place of aerial, with the voltmeter in the exit voltmeter. Be supplied the transmitter with + 12V. It will be supposed we have consumption between....
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This circuit generates a low power test signal and should not be used as a transmitter. Make sure you are within the law in the locality in which you operate this. As this was built from parts laying on the bench, it isn't optimized, but it does demonstrate....
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This project arises from the need to home-build a valid tuning control for a multi band transceiver.
It consists of a partial syntesis V.F.O. that fits to single conversion equipments with an I.F. stage
nearby 9 MHz. The circuit can cover the whole H.F.....
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This document describes the transmitter system supplied to Radio Glen for testing as designed and constructed by Henry.
The transmitter is supplied in prototype form and has the physical limitations of an instrument constructed using prototyping....
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The GHF1 is a small generator covering the HF and LF band from 30 Hz to 30 MHz in 6 ranges. The sinusoidal signal obtained can be amplitude modulated (AM) or frequency (FM).
The GHF1 also has a sweep function.
An LCD display 2 x 16 characters allows the....
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This one-valve (ECL82) CW Transmitter occupies a very special place in my amateur radio history. I was first licensed in 1994 but did not operate on air. I committed to only ever operate equipment which I had made myself. I had no time for radio construction....
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This transmitters' intended purpose is for morse-code only in the 30 meter band (10Mhz). It is a low-power QRP type and needs to be connected to your existing tranceiver. The harmonic rejections on the prototype were measured at 40dB on 20Mhz and 50dB on....
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This is a very simple 5 watt CW TX based upon a TTL logic chip. There is just one "tricky" component and this is Cx. This component should have an impedance of about 10 - 50 ohms at the frequency of interest. If you wish to reduce the transmitter power,....
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The original TX was designed to be only PULSE Modulated for a proportional R/C system, but I later used the same circuit to make an HF bands Amplitude Modulation (AM) transmitter using PA-Base Modulation. It eliminated the need for a modulation transformer;....
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Here is a simple little HF TX. It may be modified for all the HF bands, but the details given are only for the 7MHz band. The basic transmitter uses two transistors; BC547 (as usual) and will deliver over 250mW of power. CW keying may be achieved by....
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In this circuit, a 74HC14 hex Schmitt trigger inverter is used as a square wave oscillator to drive a small signal transistor in a class C amplifier configuration. The oscillator frequency can be either fixed by a crystal or made adjustable (VFO) with a....
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MC2833 MC2831 radio transmitter dedicated circuit is improved.Radio transmitter typical application circuit this circuit generates a high frequency 49.7MHz signal transmitted by the antenna out...
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A circuit diagram of the T1 is a low-impedance output transformer, it comes with 5000-8 ohm resistor. ..
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MC3335P use low-power narrowband FM receiver, you can design a very simple 80 m SSB receiver. MC3335 also has a comparator circuit..
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The coil is about 25 turns #28 wire on a T-44-6 core, tapped at about 5 turns. I'm too lazy to open my VFO and count it for you -- besides, you'll probably have to tweak it yourself with your available components. Once the turns are squeezed to the right....
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DF data transmission module operates at 315MHz, the use of surface acoustic wave resonator SAW frequency stabilization, high frequency stability. When the ambient temperature i..
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2.4G wireless keyboard receiving portion circuit diagram as follows: ..
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This is a compact three transistor regenerative general coverage receiver with fixed feedback. It`s based on the principle of the ZN414 only much higher coverage. The sensitivity and selectivity is relative good (especially on the LF and MW bands) as can be....
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No description available...
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This is a Crystal Receiver using 741 IC chip. Frequency range is between 500-1600Khz...
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No description available...
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This is a very sensitive 50Mc converter allowing you to receive the entire "Magic Band" (50Mc...52Mc) on your general coverage receiver (28Mc...30Mc). It receives all types of modulated transmissions. It all depends on the receiver used. I`ve tested this....
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This small receiver with reduced range (weight 9g, dimensions 32 x 25 mm) is suitable for slow-flyer, little boats, etc...
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With this simple project, you can have balanced lines too, simply adapting the unbalanced inputs and outputs of your hi-fi gear to become balanced, and then back to unbalanced at the other end. You can even be extra cunning, and power the remote converter....
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The FM broadcast band was moved immediately after World War II from its original spot just below 50 Mc to the present 88-108 Mc band. Hallicrafters was one company to offer receiving converters for those who had the old FM radio sets. The offerings....
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This is the simplest possible design. The local oscillator of the receiver is adjusted slightly so that its second harmonic can be used for mixing. RF leakage from the local oscillator is sufficient to drive this crystal diode mixer, which has an output at....
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This is a one tube (6J5) plus diode (1N34) circuit that converts any 8 Mc of the new FM band to the old FM band. It is assembled on a U-shaped piece of aluminum and mounted inside the radio set. I built one using old parts and carefully followed the....
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Here is my design for a modern receiving converter for pre-war FM sets. Accordingly, this article presents a design for listening to present day FM stations on a prewar FM set based on a MOSFET transistor and a TTL (transistor-transistor logic) packaged....
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This circuit has `suffered` a lot of modifications over its long life... Even the lettering on the integrated circuit was partially erased of the years.
The main motive of the mods was not that the circuit didn`t work right, but were several tries to add....
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Here is a simple radio that is easy to build and inexpensive. In fact, you probobly have all the parts you need in your junk box. You`ll be suprised at the great reception with this little set...
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The circuit is a divider by 64 used in many RF applications like as satellite receiver, digital tuners, frequency counters, PLL, etc. The heart of circuit is an IC named SAB6456, but you can use SDA2101 or other equivalent chips. Each output is NOT of the....
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This reflex radio project was inspired by Robert Bazian 's design. His reflex radio is the "darndest" thing I have seen and his spectacular results inspired me to come up with my own version! These designs are similar to two-transistor circuits used in some....
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The regen is basically an oscillator circuit with a gain control that allows the user to adjust the feedback to a point just below oscillation or, quite often, just above the critical level such that a small oscillation is present. The typical regen uses a....
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Modulation Monitor is a simple and useful circuit for hams. You can listen to on air transmission from your rig and be sure about the quality of the transmission. It requires no direct connection with the transmitter. In the prototype, headphones of 1K....
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The source connection is tapped into the tuning coil low down, as a means of impedance matching with the headphones and acts as the anode, while the drain connects with your headphones as the cathode, to complete the detector part of the circuit. According....
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The coil on the left is coil#1, and has 17 taps. The other coil is coil #3. The vertical strips are the lath material, screwed to the 1 foot long base. Holes drilled in the ends of the lath hold the dowel rod; it can be removed to change coils. The....
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Building a foxhole radio is rewarding and the basic setup is very simple. It is, however, difficult to adjust, and it may take several attempts to find a proper razor blade for the detector. This is a project that requires patience and much trial and error,....
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his coil is home-made. It is actually a single layer 'tapped' air core coil. Please refer to my special section on how to make the DRAIN Coil. Once it is made, the tapped leg goes into the middle hole (Refer to CHART I), but make sure you have the coil....
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Based on Valvo FD-1A module, TBA120, and MC1310. Operation of the receiver is based on the phase locked loop principle. The FD-1A contains an RF amplifier, oscillator and mixer (made with BF324, BF451 and BF324 transistors, respectively). Tuning is performed....
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Two conventional amplifier stages built with SF215 transistors are linked by ceramic 10.7MHz IF filters, and followed by an FM demodulator built with a TBA120T i.c. Straight from the databook. Output goes via a 100k log potmeter (not shown) to the audio....
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For this radio, which I repaired for someone, I made this DIY VL1. Later I found the real tube...
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The Nora K5W is a German radio from about 1929/1930.
Is uses the tubes: 2x REN804, 2x REN1004, RE134 or RE604, RGN1054...
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The diagram of detail of Fig.2 gives additional precise details: The signal HF collected by the antenna is amplified by T1, framed reel S of agreement L1 and L2. To vary the profit of T1, it is enough to vary its supply voltage. Here it passes from 4v to....
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The quartz QZ1 of the preceding receivers which set the work frequency is not on the market any more. It is replaced
by a locking phase loop allowing the free choice of an unspecified frequency on the band used, either the 41, or the 72 MHz. The step....
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This receptor is born of our annoyance against the irritating problem of Quartz: With the RX21, completed research of cut crystal for your personal rating, you have with him, access to ALL band frequencies, in steps of 5 kHz ! Desiring to make this universal....
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This receiver weighs about 6 g, used in 41 and 72 MHz, met a great success with readers of the magazine. The RX22 is the subject of these lines is improved RX20. Adding a preamp-HF improving sensitivity. Establishment of an automatic gain control of this....
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Stabilised tendency of catering: Vcc=9~12V. Frequency of reception: 88~108MHz. Consumption: 100mA. If you know some language of programming as C ++, PASCAL, VISUAL BASIC, DELPHI etc you can write a program which will send in the parallel door (378 I) of PC....
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The direct conversion receiver described consists of only a bandpass filter, mixer IC, VFO and audio filter. With only 22 parts, this simple circuit should take a few hours at the weekend to construct. For extra simplicity, eliminate L1 & C1 and connect C2....
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The Philco radio is a nine tube superheterodyne reciever combining standard broadcast, police and airplane reception and employs the high efficiency 6.3 volt filament tubes, automatic volume control, bass compensating tone control, shadow tuning and push....
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This circuit is an FM 88-108 MHz reciever...
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Here is a nice little receiver for narrow-band FM reception. It can also be used to receive FSK, RTTY and PACKET signals from the HF bands. Basic receiver sensitivity is in the region of 1uV PD and the receiver can be tuned to almost any frequency from....
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The frequency covered is from 0.1Hz to 10Hz and useful signals are received up to 16Hz. The first Op-Amp, properly shielded, must be installed close to the antenna (1-3m long) and connected to the rest of the circuit with a 5-core shielded cable. Adjust the....
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Using the circuit of 40-metre band direct-conversion receiver descr- ibed here, one can listen to amateur radio QSO signals in CW as well as in SSB mode in the 40-metre band. The circuit makes use of three n-channel FETs (BFW10). The first FET (T1) performs....
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Earphones, batteries are sold separately. AM / FM seems to be a common mold. But stamping is different. AM / FM E193577 UL94V0 board with the AM / FM etching printed circuit board manufacturers are the same. Shape is considered to be shared. (Design, sharing....
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This is the complete circuit of the modern homodyne receiver. This receiver can receive AM CW and SSB transmissions...
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The most commonly available headphones have an impedance of 2 × 32 ?, this relatively low value makes them unsuitable for such a design. However, with a bit of crafty transformation these headphones can be used in just such a design. To adapt them,....
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This radio reciever can work with any of the following transistors zn414, mk484 or ta7642...
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This figure is converted into the manifold LM567 SCA broadcast reception information machine schematic. LM567 narrow-band phase-locked loop center to meet the basic role of SCA broadcast demodulation...