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 Schematics  >> 

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Camera VHF Video Transmitter
This is a simple video transmitter that can transmit as far as 50 meters. This video transmitter can be used with the camera or other video sources. You can view them on VHF channel analog TV. Supply voltage to the video transmitter can use 9V battery. Transistor components that are used for a video transmitter is BC548 or you can use another type of transistor BF199. Meanwhile, other passive components used SMD type. For winding coil L1 is 5 Turns 8 mm in diameter and use wire AWG 0.3-0.5 mm.


CB Transmitter
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 0,7-1A. With a screwdriver we regulate the core of inductor L1/L2 and later the variable C6 until we see the biggest tendency. We connect the microphone and speaking we observe the clue in the multimeter. If all have become right will be supposed the tendency, speaking, to go up roughly 30-35%.


Coilless FM Transmitter
The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength. Since the output of N4-N6 is square wave there will be a lot of harmonics in it. The 9th harmonics of 10.7Mhz (96.3Mhz) will hence be at the center of the FM band. N1 is working as an audio amplifier. The audio signals from the microphone are amplified and fed to the varicap diode. The signal varies the capacitance of the varicap and hence varies the oscillator frequency which produce Frequency Modulation.


FM Broadcast Transmitter
This FM Broadcast Transmitter circuit will transmit a continuous audio tone on the FM broadcast band (88-108 MHz) which could used for remote control or security purposes. Circuit draws about 30 mA from a 6-9 volt battery and can be received to about 100 yards. A 555 timer is used to produce the tone (about 600 Hz) which frequency modulates a Hartley oscillator. A second JFET transistor buffer stage is used to isolate the oscillator from the antenna so that the antenna position and length has less effect on the frequency. Fine frequency adjustment can be made by adjusting the 200 ohm resistor in series with the battery. Oscillator frequency is set by a 5 turn tapped inductor and 13 pF capacitor.


FM Telephone Transmitter
The FM telephone circuit is built on a PC board that is so small it can easily be fitted inside the housing of a telephone making it an instant pseudo-speak earphone. This FM transmitter circuit connects in series with telephone line, steals power from it, and transmits both sides of the conversation to an FM radio tuned between 90 and 95 MHz.


FM Transmitter Bug
The goal of this project is for me personally to learn a little more about fm transmitters and fm bug making (may the HAM radio gods bless me in this pursuit). The ideal outcome of this project is a very small and full functional FM transmitter that we can stick into a plastic mint box. In order to be able to build this, we'll have to learn a lot about amplifiers, LC oscillators, mixers, antennas and FM. This project assumes you're already comfortable build your own PCB boards. If you're not please take a look at the homemade pcb's tutorial before you continue. It will help you out a lot.


FM Transmitter Circuit
Here is the circuit diagram of the simple FM transmitter using a transistor. Great performance or range is not guaranteed here, because this is an elementary design. General purpose radio frequency transistor BF 494 (Q1) is used here for obtaining FM modulation. A condenser mic is used here to pickup the sound.The condenser mic converts the sound to electrical variations and this variations are fed to the base of Q1 , which performs the amplification as well as modulation.The capacitor C2 and L1 determines the frequency of transmission.The circuit can be powered from a 9V transistor radio battery.


FM Transmitter with 2N2218
Here's simple FM transmitter circuit using medium power 2N2218 transistor. Micropohone is of electret type that connects to two input terminals and the antenna should be a copper wire from 15 to 40 cm. Below is schematic circuit of the fm transmitter.


FM Transmitter with Varactor Diode Tuning
Presented here is a low-power FM transmitter with varactor diode tuning using surface-mount devices (SMD) that will be received with a standard FM radio. Soldering surface mounted devices is not so hard and actually is quite easy. There are many designs for small FM transmitters but they have some problems. First, you need an audio amplifier to get enough modulation. Second, the antenna is attached directly to the collector. Third, the coil L must be wound by hand and adjusted by stretching. It all ads with a weak signal that tends to drift in frequency. In contrast the transmitter schematic we present here eliminates some of those problems, using varactor diode for tuning and modulation, givin great sensitivity without an audio amplifier.


High Power FM Wireless Microphone
This FM Wireless Microphone has been a very popular project with beginners and experienced constructors alike. It has been used inside guitars and as the basis of a remote control system. I do however, receive many requests for a higher powered circuit and better microphone sensitivity. This High Power FM Wireless Microphone has a better frequency stability, over 1 Km range and is good on microphone sensitivity. This has been achieved by adding an RF amplifier buffer (with 10dB gain) and an AF preamplifier to boost the modulation a little.


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Accurate LC Meter Capacitance Inductance Meter with 16F628 and LCD
Volt Ampere Meter with 16F876 Microcontroller and LCD display
 
Accurate LC Meter

Build your own Accurate LC Meter (Capacitance Inductance Meter) and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils and inductors. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging as well as reset switch and produces very accurate and stable readings.
PIC Volt Ampere Meter

Volt Ampere Meter measures voltage of 0-70V or 0-500V with 100mV resolution and current consumption 0-10A or more with 10mA resolution. The meter is a perfect addition to any power supply, battery chargers and other electronic projects where voltage and current must be monitored. The meter uses PIC16F876A microcontroller with 16x2 backlighted LCD.

50MHz 60MHz Frequency Meter / Counter with 16F628 & LCD
1Hz - 2MHz XR2206 Function Generator
60MHz Frequency Meter / Counter

Frequency Meter / Counter measures frequency from 10Hz to 60MHz with 10Hz resolution. It is a very useful bench test equipment for testing and finding out the frequency of various devices with unknown frequency such as oscillators, radio receivers, transmitters, function generators, crystals, etc.
1Hz - 2MHz XR2206 Function Generator

1Hz - 2MHz XR2206 Function Generator produces high quality sine, square and triangle waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated. Output of 1Hz - 2MHz XR2206 Function Generator can be connected directly to 60MHz Counter for setting precise frequency output.

BA1404 HI-FI Stereo FM Transmitter
USB IO Board PIC18F2455 / PIC18F2550
BA1404 HI-FI Stereo FM Transmitter

Be "On Air" with your own radio station! BA1404 HI-FI Stereo FM Transmitter broadcasts high quality stereo signal in 88MHz - 108MHz FM band. It can be connected to any type of stereo audio source such as iPod, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity throughout your home, office, yard or camp ground.
USB IO Board

USB IO Board is a tiny spectacular little development board / parallel port replacement featuring PIC18F2455/PIC18F2550 microcontroller. USB IO Board is compatible with Windows / Mac OSX / Linux computers. When attached to Windows IO board will show up as RS232 COM port. You can control 16 individual microcontroller I/O pins by sending simple serial commands. USB IO Board is self-powered by USB port and can provide up to 500mA for electronic projects. USB IO Board is breadboard compatible.

RF Remote Control 433MHz Four Channel
100m 4-Channel 433MHz Wireless RF Remote Control
 
200m 4-Channel 433MHz Wireless RF Remote Control

Having the ability to control various appliances inside or outside of your house wirelessly is a huge convenience, and can make your life much easier and fun. RF remote control provides long range of up to 200m / 650ft and can find many uses for controlling different devices, and it works even through the walls. You can control lights, fans, AC system, computer, printer, amplifier, robots, garage door, security systems, motor-driven curtains, motorized window blinds, door locks, sprinklers, motorized projection screens and anything else you can think of.
100m 4-Channel 433MHz Wireless RF Remote Control

Four button RF remote is used to turn ON / OFF four different devices independently. Any of the four outputs can be configured to work independently in either toggle or momentary mode. Outputs are buffered by BC549 NPN transistors and can drive low voltage devices directly or be connected to either 5V or 12V relays (or motors) to control appliances that use 110V / 220V mains voltage or any voltage of your choice. Multiple remote systems can be used independently to control more than four appliances in the same location by changing the address code on 433MHz receiver and remote. It is also possible to use several remotes to control the same appliance such as garage door.
 
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