Electronic Schematics On The Net

RSS Feed Homepage

Remote Telephone Ringer
2008-05-07 12:05:00
This remote telephone bell ringer allows you to use a large (and loud) external bell in place or in addition to the built in (and rather wussy) ringer in most modern telephones. This is ideal for large outdoor areas, noisy shops or those hard of hearing. Most any large bell can be used as the circuit can be easily adjusted for various supply voltages.Parts ListC1- 0.47 300V CapacitorC2 - 47uF 25V Electrolytic CapacitorR1 - 1K 1/4W ResistorR2 - 10K 1/4W ResistorR3 - 1K PotR4 - 2K 1/4W ResistorQ1 - 6A, 200V TRIACQ2 - 6A, 200V SCR (106, Etc.)D1 - 1N4774 Zener DiodeD2, D3- 1N4007 Rectifier DiodeU1- 4N33 Opto IsolatorBell - Large Bell (Fire Bell, School Bell, Etc.)Misc.- Board, Wire, Socket For U1, CaseNotes1. Virtually any TRIAC and SCR will work for Q1 and Q2 as long as the voltage rating is high enough. Q2 needs enough current capacity to handle the full load of the bell.2. To adjust R3, call the phone line on...
More About: Telephone , Remote

Weather Satellite Receiver
2008-05-07 11:38:00
The days of guessing the weather by looking at the clouds overhead have just ended. Now you can look at the clouds from above! This project will allow you to receive pictures from satellites 600 km overhead. A typical NOAA satellite can cover nearly 1/16 of the earth in a single pass! In New York, we are able to clearly capture images from mid-Hudson bay (where there was still ice in late spring), all the way down past Cuba, as well as spanning from Wisconsin to far out in the Atlantic Ocean. The clarity of the image was enough to see the individual Finger Lakes (in New York), and shadows on the underside of thunderstorms.This receiver allows you to receive weather satellite transmissions on the VHF band, where most of the polar-orbiting satellites are located. You will recognize these transmissions on the news when you see the time lapse of the clouds darting across the countryside. The weather man in this case has taken multiple images on the computer, aligned and pieced them toge...
More About: Weather , Satellite , Receiver

Data Acquisition Using INS8048
2008-05-07 11:36:00
This application note describes techniques for interfacing National Semiconductor's ADC0833 serial I/O, and ADC0804 parallel I/O A/D converters to the INS8048 family of microprocessors. A hardware and software interface example is provided for each A/D, along with a brief theory of operation.Since the INS8048 series microprocessors are single-chip, multiple I/O line, high speed devices designed as efficient controllers, the capacity to interface with analog peripherals is obvious. That the conversion be fast, inexpensive and easily expanded to accommodate a number of I/O devices is desirable.The INS8048 is a self-contained, 8-bit processor in a 40-pin dual-in-line package. It contains its own system timing, control logic and memory. All parts contain RAM (64, 128, 256 bytes) and offer the option of on-board ROM (1k, 2k, 4k depending on part). It provides extensive bit-handling capabilities, 97 instructions, and offers easy expansion for I/O and memory. The ADC0833 A/D converter is ...
More About: Data , Acquisition

Making Printed Circuit Boards (PCBs)
2008-05-01 21:33:00
Creating Printed Circuit Boards (PCBs) is easy and fun for the whole family! But read the disclaimer -- heat and corrosive chemicals are dangerous. After you've prototyped and tested your circuit design, creating a PCB will provide a sturdy and reliable backbone for your circuit and will give your project a professional finished quality. Using PCBs can even help reduce the time you spend building circuits, especially if you are producing multiple units, as you only need to follow a parts placement diagram (there's no longer any need to worry about specific interconnections).As is usually the case, there is more than one way to do it: there are numerous ways to create PCBs. They range from the time-consumming and difficult to the fully automated and expensive. Here we will attempt to describe a method we've found ideal for small production runs (say, a few prototypes to a couple of dozen--when you reach the hundreds, it will probably be easier, quicker and cheaper to outsource) o...

Stereo Encoder Oversampling For FM Transmitter
2008-04-15 14:18:00
Stereo encoder is the circuit that used in FM transmitter audio for a high quality stereo sound transmission. This stereo encoder produces an excellent crystal clear stereo sound and very good channel separation that can match with many more expensive stereo encoders that are available on the market.Below is stereo encoder (stereocoder) from Katruud Electronic with improved PCB version 3.1. that use 8x oversampling multiplexer methodDownload complete manual
More About: Encoder , Transmitter

Privacy Policy for schematronics.blogspot.com
2008-03-19 04:55:00
Privacy Policy for schematronics.blogspot.comIf you require any more information or have any questions about our privacy policy, please feel free to contact us by email at esonet@telkom.net.At schematronics.blogspot.com, the privacy of our visitors is of extreme importance to us. This privacy policy document outlines the types of personal information is received and collected by schematronics.blogspot.com and how it is used.Log FilesLike many other Web sites, schematronics.blogspot.com makes use of log files. The information inside the log files includes internet protocol ( IP ) addresses, type of browser, Internet Service Provider ( ISP ), date/time stamp, referring/exit pages, and number of clicks to analyze trends, administer the site, track user?s movement around the site, and gather demographic information. IP addresses, and other such information are not linked to any information that is personally identifiable.Cookies and Web Beaconsschematronics.blogspot.com does use cookies...
More About: Privacy , Blogspot , Privacy policy

Application of the MC1374 TV Modulator
2008-03-13 20:05:00
This application note presents the MC1374 TV modulator chip as a suitable device for applications where separate audio and composite video signals need to be converted to a high-quality VHF TV signal.This TV modulator based MC1374 IC From Motorola with wide dynamic range and low distortion audio make it particularly well suited for applications such as video tape recorders, video disc players, TV games and subscription decoders.The IC features:* Single Supply, 5.0 V to 12 V * Channel 3 or 4 Operation * Variable Gain RF Modulator * Wide Dynamic Range * Low Intermodulation Distortion * Positive or Negative Sync * Low Audio Distortion * Few External ComponentsView the datasheet - application note for more information.
More About: Application

FM AMPLIFIER SD1407 150 Watts
2008-03-09 10:13:00
This FM amplifier is originally designed by Broadcast Warehouse, based transistor SD1407 with redrawn schematic and redesigned pcb. You can drive the amplifier with maximum 1 watt input for 150 watts FM output.Working frequency 88-108 MHz VHF band II, Power supply voltage 18-28 VDC.Download : schematic, PCB all layer, top layer, bottom layer. More info ...
More About: Watts , Amplifier

Splitband Audio Limiter
2008-03-06 17:06:00
This applicationis a very high specification peak control limiter. It has fast become the essential deviation limiter for FM radioThe application divided into two parts :Broadband Limiter Splitband LimiterActive component : FET 2N5457 and Ics NE5534, 2N5532, TL071 TL072.Download schematic and component mounted in Coreldraw 12 Format.
More About: Audio

TV Transmitter Band I and III
2008-03-06 16:44:00
This TV transmitter working on VHF Band I and III, using negative sound modulation and PAL video modulation. This is suitable for countries using TV systems B and G, like Australia and Indonesia.This circuit has not been tested at UHF frequencies. The modulated sound signal contains 5.5 -6MHz by tuning C5. Sound modulation is FM and is compatible with UK TV Transmitter System I sound. The transmitter however is working at VHF frequencies between 54 and 216MHz (band I and Band III) and therefore compatible only with countries using Pal System B and Pal System G. More info...

VHF UHF TV modulator
2008-03-06 16:34:00
Simple TV Modulator that working on VHF UHF Band, the oscillator generates frequency is modulated with the video signal and the modulated carrier wave thus generated is fed into the TV set's aerial input via a cable. Then all that remains to do is tune the VHF UHF TV set to the correct frequency.The harmonics generator converts the oscillator signal into a sort of frequency spectrum containing all the multiples of 27 MHz up to about 1800 MHz. The TV modulator's output signal is made up of a large number of little peaks, each of which is a complete transmitter signal. At least one of these will always be in band I (VHF channels 2. . . 4), one in band III (VHF channels S. . .12) and many of them will be in bands IV and V (UHF channels 21.. .69). More info ...

Voice FM Transmitter Circuit
2008-03-06 16:33:00
It is illegal in most countries to operate radio transmitters without a license so take care with transmitter circuits. This FM Low Power circuit may be tuned to operate over the range 87-108MHz band II, with a range of 20 or 30 metres.Active components in this circuit are BC548 transistors. Although not strictly RF transistors, they still give good results. I have used an ECM Mic (Voice FM ) insert from Maplin Electronics, order code FS43W. It is a two terminal ECM, but ordinary dynamic mic inserts can also be used, simply omit the front 10k resistor. The coil L1 was again from Maplin, part no. UF68Y and consists of 7 turns on a quarter inch plastic former with a tuning slug. The tuning slug is adjusted to tune the transmitter. Actual range on my prototype tuned from 70MHz to around 120MHz.The aerial is a few inches of wire. Lengths of wire greater than 2 feet may damp oscillations and not allow the circuit to work. Although RF circuits are best constructed on a PCB, you can get aw...
More About: Circuit , Transmitter

FM Transmitter with 4 Transistors
2008-03-06 16:32:00
This circuit provides an FM modulated signal with an output power of around 500mW. The inputMic preamp is built around a couple of 2N3904 transistors, audio gain limited by the 5k preset.The FM Transmitter oscillator is a colpitts stage, frequency of oscillation governed by the tank circuit made from two 5pF capacitors and the inductor. Frequency is around 100Mhz with values shown. Audio modulation is fed into the tank circuit via the 5pf capacitor, the 10k resistor and 1N4002 controlling the amount of modulation. The oscillator output is fed into the 3.9 uH inductor which will have a high impedance at RF frequencies.The output stage operates as a class D amplifier , no direct bias is applied but the RF signal developed across the 3.9 uH inductor is sufficient to drive this stage. The emitter resistor and 1k base resistor prevent instability and thermal runaway in this stage. More info ...

Microphone FM Transmitter
2008-03-06 16:30:00
This simple transmitter operates from a 9V battery as shown above. The old FM mic system was not a perfect solution, so I built this kit and a mixer for the receivers. using three separate transmitter circuits and a mixer on the receiever, the choir voices were perfect and cleanly reproduced."From the notes I made experimentally, C3 is vital to the circuit and without it the circuit may become unstable. C4 is in parallel with C5 and presents a moderate load impedance. Finally all transistors are NPN. The circuit works well and has proved reliable. More Info ...
More About: Microphone , Transmitter

Preamplifier 88-108 MHz
2008-03-06 16:28:00
This VHF amplifier working on Band 2 Radio Spectrum tuning approximately 88 - 108 MhzThe Preamplifier circuit uses two 2N3819 FET's in cascode configuration. The lower FET operates in common source mode, while the upper FET, operates in common gate, realising full high frequency gain. The bottom FET is tunable allowing a peak for a particular station.Coil details follow:L1 4 turns of 18swg air spaced with a 1cm diameter, the tap is one turn up from earth end...L2 4 turns of 18swg air spaced with 1 cm diameter. The coupling coil is 1 turn interwound from the supply end. Enamel coated wire must be used. More info ...

Making Simple TV transmitter
2008-03-06 16:26:00
(1) Soundless versionYou are familiar with the most simplest FM transmitter" that I designed (left). Let's try to transform it into a TV transmitter. Just change the input from the audio to the video (video camera or VCR) and check the signal at your television set: in Europe, for instance, choose the channel 2 - 4 and turn the trimmercap ot the transmitter. You will find some images or might watch a clear image. This suggests that it will be not so difficult to build a TV transmitter.(2) Advanced Version (AV)When you succeed in this version to work, you may try the advanced version (pdf). In this version, stability and quality are improved. This can have even the audio too. However, in order to complete this, you have to use a proper frequency counter. More info ...
More About: Simple , Transmitter

FM Transmitter With Transistor 2SC1815
2008-03-06 16:23:00
Will have to introduce a system of simple and small FM transmitter. Not only does it meet the requirements of the launch distance, but also at the same time using microphone and voice input signal line, background voice. Modulation circuit surveillance has also joined the table first, so that they can better control and the proper use of transmitters, the following circuit diagram, read briefly, whether it's just like a radio station equipment as many functions. Yes, this small transmitter can help you easily set up an amateur FM radio stations! 500 M in the coverage around. Echocardiography the bar, act immediately!Principle small FM transmitter circuit components and options:Signal to the microphone after intake, the C1 coupling into the BG1 and external circuit voltage of the single negative feedback amplifier, the voltage signal amplification weak enough to enlarge the extent of U1A and the line to enter the input signal with a mixed U1B. Mixed signal modulation way to the R17 ...
More About: Transistor , Transmitter

uPC1651 FM transmitter
2008-03-06 16:21:00
The circuit has been produced by Japan's NEC as a major upc1651 IC devices, the high gain circuit, work stability, thereby ensuring the microphone performance. Use of FM transmitter. Used it 40 - 50 cm soft drag line for antenna, the effective range of more than 30 launch M. L carefully spacing adjustment and fine-tuning capacitor, will launch frequency coverage for 88 - 108 Mhz. Map L enameled wire with diameter of 0.51 mm in diameter, 4 mm cylindrical Tuitai from around 5 laps. More info ...
More About: Transmitter

CD4066 FM Stereo Encoder
2008-03-06 16:19:00
Circuit schematics IC1-4069 in the Y1, Y2 formation of a 76 KHZ frequency of the oscillator, the Y3-Y6 isolation plastic, into IC2 dual JK flip-flop CD4027 composed of two components-frequency circuit, a symmetrical + / 38KHZ-19 KHZ and the square wave, + / -38 KHZ IC3 the square used to control analog switches CD4066, a stereo audio input signal after switching modulation used for the 19 KHZ frequency mixed signal to the transistor into FM 9014 after isolation Modulator.Click to access the debug FM modulator and 5 V power supply, with a multimeter measured IC1CD4069 the legs and IC2 CP, Q, Q, the legs should be half the supply voltage, the oscillator has been start-up. If a digital frequency meter measured IC1 output frequency, frequency regulation RW1 to 75 KHZ + /-10HZ can. If not, can be transferred to the prospective radios, RW2 half-good, and then transferred RW1, the bright lights stereo radio, and no speakers in the temple frequency whistle sounds. From the input into the st...
More About: Encoder

High Quality wireless microphone Macsot MR-700
2008-03-06 16:16:00
This is collected by the Macsot MR-700 wireless microphone system launch of the circuit for maintenance reference. High Quality Audio on receiver output.Active components:Microphone or Audio Preamplifier with IC MC4458Dynamic Audio processed with one NE571 From PhilipsFrequency Oscillator generated by one crystal 20.05 MHz and Varactor diode 2CB11A. No drift frequency is guaranted.9V DC power supply or battery. More info ...
More About: Wireless

PLL FM Transmitter With BH1415F 500mW
2008-03-06 16:14:00
This article is wang1jin (Old: Primary Color love) for the design of RF EDNCHINA.COM FM transmitter board for further analysis, making friends for reference. This EDNCHINA PCB board can be free. Need friends can make reference to relevant websites Learn more.Designed with PLL technology, BH1415 FM transmitter system block diagram, LCD1602 from STC2052 + + M62429 MIC + + + BH1415 infrared keyboard amplification and high frequency components.(Website procedural reasons, the picture may not clear to the local Save Show) More info ...
More About: Transmitter

MC145151 PLL FM Stereo Transmitter
2008-03-06 16:11:00
This transmitter use pll chip MC145151 from Motorola and stereo encoder chips BA1404 with vco built in. BA1404 from MC145151 is to overcome the single-frequency instability in the BA1404. Modulation of the emission control BB910 frequency. B571C kept in control procedures, the procedures required to prepare another.Amplifier section of this FM Stereo transmitter use 2sc2053 with power 250 mWatt out.
More About: Transmitter

300mW FM Transmitter 2SC2538
2008-03-06 16:10:00
The FM transmitter using a varactor diode way radio, plus a Class C amplifier, RF output power of up to 300 mW more open to more than one kilometer distance communications. Select components: Q1 with ? 100 mA, Ft ? 300 MHz, ? ? 100 tubes available 3 DG82, 3DG122, 3DG130, 2G711; Q2 with 2SC2538, 2SC1970, etc.. It must be noted that RF Baffles circle L8, L9, L10; C13, C14, C17, C18, C19, and so can not be omitted, otherwise it would cause unnecessary self-excited oscillation. L1, L5 need to tap extraction, data such as icons, not otherwise due to impedance matching, the output power of less than maximum. Such as a battery-powered, Q3 (Darlington tube), C15, R6 can be omitted. ebugging steps: first in the output termination of testing circuit to regulate the C7, C9, C12 to the largest multimeter readings, remove test circuit connected to one meter in length pole antenna to pull to fine-tune C12 simple reading of the largest field will be completed debugging.
More About: Transmitter

UHF Push Pull For TV Translator With BLV859
2008-02-18 16:13:00
A broadband linear amplifier design is presented, suitable for application in TV transposers operating in band IV and V (470 to 860 MHz). The design is based on two BLV859 bipolar transistorscombined with quadrature hybrids. Typical results at the recommended class-A bias point (25.5 V/9.1 A) for the total module include 40 W peak sync output power at -54 dB three tone IMD level (fvision = -8 dB, fsound = -10 dB, fsideband = -16 dB) and an average gain of 10.5 dB in the (470 to 860) MHz range.The BLV859 is a bipolar linear push-pull power transistor designed to operate in the 460 to 860 MHz range. With a specified output power of 20 W peak-sync in class-A it is the largest device in the new generation of transposer transistors. The intermodulation distortion level is 10 dB at 860 MHz. For application in TV transposers for Band IV/V (470 to 860 MHz) a wideband linear power amplifier has been designed with two BLV859 transistors in class-A.The amplifier consists of 2 balanced circuits...
More About: Translator , Pull , Push

470 - 860 MHz Wideband Amplifier Construction
2008-02-09 15:51:00
INTRODUCTION In the application report NCO8101 two amplifiers for band 4/5 with BLV57 transistors have been described. Reactions on this report proved the necessity to give more information about the construction of these amplifiers. This construction has been based on a heatsink with a printed-circuit board at the upper side and the bias circuits and a forced air-cooling at the lower side. (download datasheet)PRINTED CIRCUIT BOARD In the printed-circuit board rectangular holes have been made to mount the BLV57 transistors on the heatsink. For fastening of the printed-circuit board on the heatsink by means of screws, 7 holes of 3.1 mm Æ and for fastening of the hybrid couplers 8 holes of 2.6 mm Æ have been made on the indicated places (see Figs 1 and 2). Hereby has been taken into account the use of Anaren hybrid couplers, type 10264 - 3, suited for the frequency range of 500 - 1000 MHz. Because the 2 bias units have been situated at the lower side of the heatsink, the connections ...
More About: Construction , Wideband , Amplifier

UHF TV RF Amplifier 470-860 MHz
2008-02-06 05:56:00
Working Frequency 470-860 Mhz UHF Band IV and V. Power out of the RF Amplifier about 14 Watts with power input 1.5 Watts. ( Transistor Datasheet)Schematic Part Lists :C1 = C6 = C16 = 4,7 pF (500 V) multilayer ceramic chip capacitorC2 = C3 = C20 = C21 = 33 pF multilayer ceramic chip capacitorC4 = C9 = C13 = C19 = 1,2 to 3,5 pF film dielectric trimmerC5 = C7 = C15 = C17 = 100 nF multilayer ceramic chip capacitorC8 = C10 = C11 = C12 = 220 pF multilayer ceramic chip capacitorC14 = C18 = 6,8 mF/40 V solid aluminium electrolytic capacitorC22 = C23 = 1 pF (500 V) multilayer ceramic chip capacitorL1 = L2 = L13 = L14 = Coax. 50 Ohm with diameter 2,2 mm; lenght 29,0 mm, soldered on striplines75 W (1,1 mm ´ 28,0 mm). inner L1 dan L13 not connectedL3 = L4 = 52 W stripline (2,0 mm ´ 16,5 mm)L5 = L8 = 470 nH microchokeL6 = L7 = 39 W stripline (3,1 mm ´ 8,0 mm)L9 = L12 = 1 Turn (1,0 mm); diameter 5,5 mm; lead space 2 ´ 3,5 mmL10 = L11 = 39 W stripline (3,1 mm ´ 34,0 mm)L3, L4, L6, L7, L10 dan L11 ...

Broadband UHF TV Power Amplifier With BLV861
2008-02-06 05:20:00
The TV amplifier has been tuned under class-A small-signal conditions and characterised under large signal class-AB conditions from 470 - 860 MHz. (All Datasheets)Schematic Circuit Amplifier The total description of the amplifier is given in Figs 6 and 7 and Table 8 (in datasheet). The amplifiers input and output matching networks contain mixed microstrip-lumped elements networks to transform the terminal impedance levels to approx. 25 W balanced. The remaining transformation to 50 W unbalanced is obtained by 1 : 2 balun transformers. The baluns B1 and B2 are 25 W semi-rigid coax cables with an electrical length of 45° at midband and a diameter of 1.8 mm, soldered over the whole length on top of microstrip lines. To keep the circuit in balance two stubs L1 and L8 with the same length have been added. For low frequency stability enhancement the input balun stubs are connected to the bias point by means of 1 W series resistors. Large capacitors (C4 and C11) are added at the biasing poi...
More About: Power , Broadband

Microwave Power Meter
2008-02-05 15:31:00
Article from Hans Wagemans, ON4CDU A sensitive power meter is a very useful instrument when doing experiments. A few years ago when I started my microwave radio hobby up again, the first project I undertook was building a 23 cm transverter. During the development, a diode in front of my analog meter (VOM) was used to tune the microwave circuits to the resonance frequency. During the experiments, the need for a more sensitive and precise power meter was recognised. After some experiments it turned out that, based on the principle of the diode rectifier with a cheap amplifier behind it, a simple, but also sensitive and accurate power meter could be built. The circuitThe input circuit consists of a 'wide dynamic range' RF diode detector. This 'wide dynamic range' is obtained by applying a bias current of about 25 uA through the detector diode (D2). When using different diodes, the current can be adjusted by changing the 220 k resistors. Due to the bias current the detector has a go...
More About: Power , Microwave , Meter

Protector Circuit For RF Amplifier
2008-02-05 15:23:00
This circuit protector is so simple, but it has big function in protecting your rf amplifier device. The input part signals for protecting are :Termo Switch (Heat Sensor Resistance) from your active component, RF Power transistor/FET.Forward and Reflect (reverse) from your directional coupler after your Low Pass Filter Output.Over Drive from directional coupler at the input of your rf amplifier to limit power input in normal condition.Relay (12v DC) for disconnecting power supply of your RF amplifier if condition for protecting happened. Note :Do it manually before you install it in real condition. Don't forget to adjust 50K resistor for every input parts.
More About: Circuit , Protector , Amplifier