Showing posts with label transmitter. Show all posts
Showing posts with label transmitter. Show all posts
Thursday, October 16, 2014
TV audio video transmitter Schematic Diagram
This is a simple TV audio video transmitter circuit can be constructed using this schematic diagram . This TV audio video transmitter circuit can be used to transmit video signals from VCR ( or some other device ) to a TV without using any cable .
Video signals input at jack J1 are first terminated by resistor R6 and coupled through capacitor C1 to clamping-diode D1. Potentiometer R3 is used to set the gain of the video signal; its effect is similar to that of the contrast control on a TV set.
TV audio video transmitter Schematic Diagram
Bias-control R7 can be used to adjust the black level of the picture so that some level of signal is transmitted, even for a totally dark picture.
RF-transformer T1 and its internal capacitor form the tank circuit of a Hartley oscillator thats tuned to 4.5 megahertz. Audio signals input at J2 are coupled to the base of Q3 via C2 and R4: the audio signal modulates the base signal of Q3 to form an audio subcarrier that‚s 4.5-megahertz higher than the video-carrier frequency.
The FM modulated subcarrier is applied to the modulator section through C5 and R9.
Resistor R9 adjusts the level of the subcarrier with respect to the video signal.
Resistor R9 adjusts the level of the subcarrier with respect to the video signal.
Transistors Q1 and Q2 amplitude modulate the video and audio signals onto an RF-carrier signal. The operating frequency is set by coil L4, which is 3.5 turns of 24- gauge enameled wire on a form containing a standard ferrite slug.
The RF output from the oscillator (L4, C7 and C9 ) section is amplified by Q5 and Q6, whose supply voltage comes from the modulator . Antenna matching and low-pass filtering is performed by C12, C13, and L1.
Resistor R12 is optional; it is added to help match the output signal to any kind of antenna.
To align this audio video transmitter you need to tune a TV receiver to an unused channel between 2 and 6. The TV must have an indoor antenna connected directly to it; an outdoor antenna or cable wont work. Make sure both potentiometers (R3, R7) are in middle position and apply power to the transmitter. Adjust L4 with a nonmetallic tool until the TV screen goes blank ,then fine-adjust L4 for the "most-blank" picture.
Connect the video and audio outputs from a VCR(AV source) to jacks J1 and J2 (respectively) of the transmitter .
After that you should see a picture on the TV screen: if you do, readjust L4 for the best picture; if you dont, check the board for any bad connections. Next, adjust R3 for the best picture brightness and R7 for the best overall picture.
Finally, adjust T1 with a nonmetallic tool for the best sound .
The TV transmitter combines line level audio and video signals, and transmits the resulting signal up to 300 feet. The circuit can be powered from a 9-12V power supply circuit .
Saturday, September 20, 2014
Wireless transmitter microphone circuit
Wireless FM transmitter circuit Microphone Hi Fi using a model-ready transmitters, this is because the buil-up transmitter module has a transmission capability of a stable and very effective to emit 10 mW RF. so that the target of Hi Fi FM Wireless Microphone transmitter circuit Hi Fi can be realized. The series can be seen from the FM transmitter Microphone Wireless Hi Fi transmitter module is that it stands alone with an additional R7, R8 and C6 to produce high-quality RF frequency.
In the series of FM transmitter Microphone Wireless Hi Fi module requires power consumption of a battery 12 VDC. Transmission antenna is directly connected with the circuit module Wireless FM transmitter Wireless FM Microphone Hi Fi.
Input section of the circuit transmitter Wireless FM Microphone Hi Fi signals to the modulation of 100mV RMS. A microphone preamplifier with IC TL081 is used to reproduce the signal from the microphone into a signal with 100mV rms level as needed this wireless FM transmitter module. strengthening the signal from the microphone preamplifier circuit in FM transmitter Microphone Wireless Hi Fiini regulated by P1. R1, R2 and C1 in the range of an FM transmitter Microphone Wireless Hi Fi is used to provide supply to the microphone electred used.
Thursday, September 11, 2014
Medium power FM transmitter circuit
This is the schema diagram of a moderate power FM transmitter schema employing two transistors.The voice signals picked by the microphone will be amplified by the transistor Q1.The second transistor is wired as an oscillator operating in the FM band.The output of T1 is given to the base of T2.T2 performs the modulation also.The tank schema comprising of components L1 and C6 determines the frequency of the signal, and can be varied by adjusting C6.The capacitor C7 couples the FM signal to the antenna.
Notes.
* You can assemble the schema on a general purpose PCB.
* The schema can be powered from a9V PP3 battery.
* The Antenna A1 can be a 1M long wire.
* The inductor L1 can be made by making 6 turns of 0.8mm enameled copper wire on a 5.5mm diameter/4.5mm length plastic former.
* With a matching antenna and proper tuning this transmitter can have range upto 100meters.
Monday, September 8, 2014
Tracking Transmitter
This is a tracking transmitter.Normally we use these thing to track animals,Rc planes etc.The power of this one is about 3.7mA.This schema can be operated by using 1.5V button cell.The operating frequency is FM 100Mhz .But if you want to use it between 108Mhz to 88Mhz you have to use Just spread the windings of the coil just a bit About 1/2 a millimeter .This is wonderful project. Have fun with this.
Note
#This is not long range one but you can get the maximum advantage
#supply 1.5 v
#Attach 12 inch antenna
#Search until mmmmh mmmmmh mmmmmh mmmmmh sound comes from your radio set
Saturday, September 6, 2014
Low Power Atv Jr Transmitter 440Mhz Wiring diagram Schematic
Low Power Atv Jr Transmitter 440Mhz Circuit Diagram. This low-power video transmitter is useful for R/C applications, surveillance, or amateur radio applications. Seven transistors are used in a crystal oscillator-multiplier RF power amplifier chain, and a high-level video modulator. A 9- to 14-Vdc supply is required. Output is 0.4 to 1.2 W, depending on supply voltage.
Low Power Atv Jr Transmitter 440Mhz Circuit Diagram
Sunday, August 31, 2014
Simple FM transmitter circuit 88 108MHz
This is simple transmitter schema diagram.This schema has some what good coverage.To tune this schema use 88MHz-108MHz radio.This schema can be operated with 9-12V power supply.This schema needs 30mA.
Note
#In some countries transmitters have been banned.so dont misuse this schema.We just wanted to give you an extra knowledge about it.If somebody used this for unnecessary things we cant get the responsibility of it.
Wednesday, August 20, 2014
2 Watt FM Transmitter Wiring diagram Schematic
CIRCUIT DESCRIPTION
The schema is basically a radio frequency (RF) oscillator that operates around 100 MHz. Audio picked up and amplified by the electret microphone is fed into the audio amplifier stage built around the first transistor. Output from the collector is fed into the base of the second transistor where it modulates the resonant frequency of the tank schema (L1 coil and the trimcap) by varying the junction capacitance of the transistor. Junction capacitance is a function of the potential difference applied to the base of the transistor T2. The tank schema is connected in a Hartley oscillator schema.
Components List
R1=220K R2=4.7K R3,R4=10K R5=100ohm | C1,C2=4.7uF Electrolytic C3,C4=1nF C5=2-15pF C6=3.3pF | Q1=BC547C Q2=BD135 P1=25K MIC=Electret Condenser Type |
Monday, August 18, 2014
FM Radio Transmitter schematic with pcb
For those of you like / love to talk in the air can assemble this simple circuit that can be received by the radio receiver to within a few hundred feet. The voice that issues by this circuit at all clear without rustling. Can also be used to link communications over the air using this radio transmitter, provided that other person also had the same circuit.
This PCB design :
Description :
Resistor
R1__________________1K
R2__________________18K
R3__________________82K
R4__________________1K2
R5__________________5K6
R6__________________39K
R7__________________18K
R8__________________68K
R9__________________470R
R10_________________100R
R11_________________50K
XTal
Q1__________________ Crystal according to the desired frequency
Inductor
L1__________________10uH
Capacitor
C1__________________10uF
C2__________________30uF
C3__________________20uF
C4__________________47uF
Transistor
Tr1_________________2SB175
Tr2_________________2SB175
Tr3_________________2SB178
Antenna
X1-1________________10-20 meters
Connector
X2-1________________Ground
X2-2________________VCC 9-12 Volts DC
X3-1________________Input
X3-2________________Ground
Thursday, August 14, 2014
FM Transmitter circuit diagram 50M
This is FM transmitter schema diagram.By using this schema diagram you can send signals up to 50M.Here I have used 2N2222 Transistor.This schema can be operated with 3V
Note
# L1= 5 turns of 24AWG wire on a 1cm plastic former.
# Antenna can be a 25cm long 18AWG wire.
Wednesday, August 13, 2014
Simple FM Transmitter
This FM transmitter claimed to be a very good transmitter. This schema is worked very well since this schema is actually copied from available electronic kit.
Component part:
Frequency range is 100-108 MHz. The schema is only mono schema, and accepts an audio input from either a microphone or other source. The input impedance is 1Mohm. The input sensitivity is 5mV and the max input signal is 10mV. The transmitted signal can be picked up on a FM radio. The schema can be used for short-range transmission, eg. for wireless microphones.
The power supply to use is 9-14 V DC, one of the little rectangular 9V batteries is fine. Connect this to the + and - points on the PCB. The sound input goes to the points marked "MIKE". The antenna should be connected to the point marked "ANT". The emitters output impedance is 50 ohms. You can make your own fancy antenna if you like.
Source: http://www.high-voltage-lab.com/77/small-radio-transmitter
Read More..
Component part:
R1 100K R2 220K R3 22R R4 1K trimmer R5 1K R6 56K R7 1M R8 1K2 T1 BF244A or BF245A FET T2 2N3819 FET T3 BC307/8/9 or BC557/8/9 PNP | D1 Varicap diode (eg. BB119) D2 1N4148 C1 5pF ceramic C2 6pF ceramic C3 15pF ceramic C4 trimmer cap C5 15pF ceramic C6 1nF ceramic C7 100uF electrolytic C8 4.7uF electrolytic C9 100pF ceramic |
Frequency range is 100-108 MHz. The schema is only mono schema, and accepts an audio input from either a microphone or other source. The input impedance is 1Mohm. The input sensitivity is 5mV and the max input signal is 10mV. The transmitted signal can be picked up on a FM radio. The schema can be used for short-range transmission, eg. for wireless microphones.
The power supply to use is 9-14 V DC, one of the little rectangular 9V batteries is fine. Connect this to the + and - points on the PCB. The sound input goes to the points marked "MIKE". The antenna should be connected to the point marked "ANT". The emitters output impedance is 50 ohms. You can make your own fancy antenna if you like.
Source: http://www.high-voltage-lab.com/77/small-radio-transmitter
Tuesday, August 12, 2014
Simple Solar Powered Long Range FM Transmitter Wiring diagram Schematic
Build a Simple Solar Powered Long Range FM Transmitter Circuit Diagram. This is very stable, harmonic free, long range fm transmitter schema which can be used for fm frequencies this one is unique in that it runs completely on solar power. No battery is required. As long as the sun is shining on the PV panel, the transmitter will transmit. The transmitter bug is useful as a "remote ear", and can be used for anything from listening birds to surveillance work. The mic preamp and oscillator diagram were borrowed from a common schema found around the Internet, a regulated solar power supply and an RF amp that extends the range of transmitter and improves frequency stability were added.
Simple Solar Powered Long Range FM Transmitter Circuit Diagram
Theory
The solar power supply consists of a small 18V PV panel which charges a 1000uF electrolytic capacitor. The capacitor keeps the schema running during brief interruptions of light, such as a bird flying over the PV panel. The 18V is regulated down to 9V with the 78L09 regulator IC to provide a steady 9V supply for the rest of the schemary. With the PV panel shown above, the schema will only work when direct sunlight is shining on the panel. A larger panel that can provide 22mA at 12V during cloudy conditions would extend the diagram operating conditions.
The Electret microphone is biased with a 33K resistor, the resistor value can be changed to vary the amount of modulation and optimize the performance of specific microphones. The microphone signal is amplified by a 2N3904 audio amplifier. This signal is sent to the 2N2222A oscillator stage where it changes the oscillators frequency (FM). The oscillators operating frequency is set by L1, the 6pF capacitor and the 5-20pF variable capacitor. With L1 wound as specified on the schematic, the schema will operate near the low end (88Mhz) of the FM broadcast band.
The output of the oscillator schema is taken from a tap on the oscillator coil L1 and fed to the RF amplifier 2N2222A transistor. The output of the RF amp is run through a low pass PI filter to remove unwanted RF harmonics before the signal is sent to the antenna.
Specifications
Output Frequency: 88Mhz nominal, can cover 88-108Mhz with coil adjustments
Input voltage: 11-18VDC
Operating current: 22mA @18VDC
DC input to RF amp: 81mW
RF output power: 40mW (approx.)
Construction
The prototype schema shown in the top photo was built using the "dead bug" construction method, it was laid out as the schema was designed. A second-generation version of the schema was built using a home-made printed schema board, this is shown in the second photo. The frequency stability of the transmitter was greatly improved when it was built with the schema board. Artwork for the PCB is available at the end of this page.
It important to mount the oscillator components solidly so that they dont move around and cause unwanted frequency shift. The component leads for all of the RF wiring should be kept short. The coils were wound on a #2 Philips screwdriver shaft and stretched out a bit. To improve the diagram frequency stability, wind the oscillator coil on a 1/4" form, then heat the coil in an oven at to anneal the metal. A layer of polystyrene "Q dope" can be painted onto the coil to further improve the stability.
Another trick that will improve the transmitters frequency stability is to build it into a metal box that is surrounded by an insulating material such as styrofoam or bubble-wrap. If the transmitter box is mounted in the shade, it will be less likely to change frequency due to solar heating and cloud shading.
Antennas
This schema will work with a variety of antennas. An adequate short-range antenna can be as simple as a 1 to 2 wire connected directly to the schema. A resonant antenna such as a tuned dipole or a vertical antenna will greatly extend the range of the transmitter.
A resonant half-wave diple antenna for 90Mhz can be made with two 2.6 foot pieces of wire fed in the middle, using the classic dipole formula: quarter wave length (feet) = 234 / frequency (Mhz). the PV panel and wiring should be kept away from the antenna, or in the case of a short whip antenna, the PV wiring can be run in the opposite direction as the antenna to act as the other half (counterpoise) of a dipole.
Alignment
The schema can be aligned in the laboratory by putting 12V to 18V DC across the PV panel to power the regulator. Tune your receiver to a blank spot on the lower end of the FM band and adjust the frequency calibration trimmer until you hear the microphone signal. Turn the trimmer very slowly, alignment takes a light touch. Dont turn the receiver volume up too much or you will get audio feedback. A frequency counter may be useful for setting the output frequency. It may be necessary to retune the frequency a bit after the schema has warmed up in the sun.
The output capacitor should be tuned for the maximum transmitted signal, this setting varies with different antennas. The best way to do this is to connect the antenna to the transmitter and monitor the signal with an oscilloscope (100 Mhz bandwidth) connected to a nearby antenna. Adjust the control for the highest signal. If you have a receiver with a signal strength indicator, that can also be used for monitoring the transmitters output level. Adjustment of the output capacitor will pull the oscillator frequency a bit, it will be necessary to alternate between oscillator and output adjustments to fully align the schema.
Use
Place the PV panel in the sun and tune your receiver to the bugs signal, listen to the world outdoors. An analog receiver is best for picking up the signal since, unlike a digital receiver, it can be fine tuned to track the signal. I use a 1970s vintage Pioneer receiver to good effect. Once the bugs temperature has stabilized, its frequency should not drift very much.
The microphone enclosure and placement can be tuned to optimize sound reception in a particular direction. A good directional microphone can be made by putting the mic element into one end of a short piece of PVC pipe. Inserting a thin tube of porous foam into the pipe can lower the resonant nature of the cylinder.
The solar power supply consists of a small 18V PV panel which charges a 1000uF electrolytic capacitor. The capacitor keeps the schema running during brief interruptions of light, such as a bird flying over the PV panel. The 18V is regulated down to 9V with the 78L09 regulator IC to provide a steady 9V supply for the rest of the schemary. With the PV panel shown above, the schema will only work when direct sunlight is shining on the panel. A larger panel that can provide 22mA at 12V during cloudy conditions would extend the diagram operating conditions.
The Electret microphone is biased with a 33K resistor, the resistor value can be changed to vary the amount of modulation and optimize the performance of specific microphones. The microphone signal is amplified by a 2N3904 audio amplifier. This signal is sent to the 2N2222A oscillator stage where it changes the oscillators frequency (FM). The oscillators operating frequency is set by L1, the 6pF capacitor and the 5-20pF variable capacitor. With L1 wound as specified on the schematic, the schema will operate near the low end (88Mhz) of the FM broadcast band.
The output of the oscillator schema is taken from a tap on the oscillator coil L1 and fed to the RF amplifier 2N2222A transistor. The output of the RF amp is run through a low pass PI filter to remove unwanted RF harmonics before the signal is sent to the antenna.
Specifications
Output Frequency: 88Mhz nominal, can cover 88-108Mhz with coil adjustments
Input voltage: 11-18VDC
Operating current: 22mA @18VDC
DC input to RF amp: 81mW
RF output power: 40mW (approx.)
Construction
The prototype schema shown in the top photo was built using the "dead bug" construction method, it was laid out as the schema was designed. A second-generation version of the schema was built using a home-made printed schema board, this is shown in the second photo. The frequency stability of the transmitter was greatly improved when it was built with the schema board. Artwork for the PCB is available at the end of this page.
It important to mount the oscillator components solidly so that they dont move around and cause unwanted frequency shift. The component leads for all of the RF wiring should be kept short. The coils were wound on a #2 Philips screwdriver shaft and stretched out a bit. To improve the diagram frequency stability, wind the oscillator coil on a 1/4" form, then heat the coil in an oven at to anneal the metal. A layer of polystyrene "Q dope" can be painted onto the coil to further improve the stability.
Another trick that will improve the transmitters frequency stability is to build it into a metal box that is surrounded by an insulating material such as styrofoam or bubble-wrap. If the transmitter box is mounted in the shade, it will be less likely to change frequency due to solar heating and cloud shading.
Antennas
This schema will work with a variety of antennas. An adequate short-range antenna can be as simple as a 1 to 2 wire connected directly to the schema. A resonant antenna such as a tuned dipole or a vertical antenna will greatly extend the range of the transmitter.
A resonant half-wave diple antenna for 90Mhz can be made with two 2.6 foot pieces of wire fed in the middle, using the classic dipole formula: quarter wave length (feet) = 234 / frequency (Mhz). the PV panel and wiring should be kept away from the antenna, or in the case of a short whip antenna, the PV wiring can be run in the opposite direction as the antenna to act as the other half (counterpoise) of a dipole.
Alignment
The schema can be aligned in the laboratory by putting 12V to 18V DC across the PV panel to power the regulator. Tune your receiver to a blank spot on the lower end of the FM band and adjust the frequency calibration trimmer until you hear the microphone signal. Turn the trimmer very slowly, alignment takes a light touch. Dont turn the receiver volume up too much or you will get audio feedback. A frequency counter may be useful for setting the output frequency. It may be necessary to retune the frequency a bit after the schema has warmed up in the sun.
The output capacitor should be tuned for the maximum transmitted signal, this setting varies with different antennas. The best way to do this is to connect the antenna to the transmitter and monitor the signal with an oscilloscope (100 Mhz bandwidth) connected to a nearby antenna. Adjust the control for the highest signal. If you have a receiver with a signal strength indicator, that can also be used for monitoring the transmitters output level. Adjustment of the output capacitor will pull the oscillator frequency a bit, it will be necessary to alternate between oscillator and output adjustments to fully align the schema.
Use
Place the PV panel in the sun and tune your receiver to the bugs signal, listen to the world outdoors. An analog receiver is best for picking up the signal since, unlike a digital receiver, it can be fine tuned to track the signal. I use a 1970s vintage Pioneer receiver to good effect. Once the bugs temperature has stabilized, its frequency should not drift very much.
The microphone enclosure and placement can be tuned to optimize sound reception in a particular direction. A good directional microphone can be made by putting the mic element into one end of a short piece of PVC pipe. Inserting a thin tube of porous foam into the pipe can lower the resonant nature of the cylinder.
Parts
1X GM 684 60 mA 18V PV panel (available from Electronix Express) or equivalent
1X 78L09 voltage regulator IC
1X 1N4001 diode
1X 2N3904A transistor
2X 2N2222A transistors
1X 1000uF 25V electrolytic capacitor
1X Electret microphone
4X 100nF capacitors
2X 22nF capacitor
1X 1nF capacitor
1X 3pF silver mica capacitor
1X 6pF silver mica capacitor
1X 10pF silver mica capacitor
1X 20pF ceramic disk capacitor
1X 27pF ceramic disk capacitor
2X 5-20pF (or similar) miniature variable capacitor
1X six hole ferrite choke or equivalent
1X 100 ohm 1/4W resistor
1X 470 ohm 1/4W resistor
1X 10K 1/4W resistor
1X 20K 1/4W resistor
1X 33K 1/4W resistor
1X 47K 1/4W resistor
1X 1M 1/4W resistor
1X 1-3/4"x3" copper plated blank printed schema board
1 length of #20 tinned copper hookup wire for making two coils
1X weatherproof plastic box (recommended)
Sourced By: Copy righted : G. Forrest Cook
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