Electronic Circuits and Tutorials
Electronics Schematics - T

Transmitter Circuits

1 Watt RF Amplifier -  This is a universal 1 Watt RF class C amplifier that is ideally suited for low power FM transmitters. Input should be at least 100mW to achieve 1W output. It is recommended to enclose the amplifier in a metal case.

1.3W VHF RF Amplifier 2SC1970 88-108 MHz -  This RF power amplifier is based on the transistor 2SC1970 and 2N4427. The output power is about 1.3W and the input driving power is 30-50mW. It will still get your RF signal quit far and I advice you to use a good 50 ohm resistor as dummy load. To tune this amplifier you can either use a power meter/wattmeter, SWR unit or you can do using a RF field meter.

1.5V Battery operated FM rebroadcast transmitter  -  This implementation is adapted to rebroadcast the output of a CD player, television receiver, or radio receiver. I use it so that I can move about the house and listen to my favorite programs without disturbing others. Within and the house....

1.5V Tracking Transmitter (with Video Clip) -  The current draw for this tracker is 3.7mA, so the 1.5V button cell will last awhile. What the heck am I suppose to hear you ask? When your circuit is working you should see the LED flash quite fast. Take your FM radio and search for the low-beat 'humbe-humbe-humbe-etc' equal to the flash of the LED (Tony van Roon's probably around the 100Mhz). Found it? If that position is interfere ring with a radio station....

1.5W VHF Amplifier -  This project will explain the basic function of a class-C transmitter. I will explain how to dimension a transmitter and the purpose of the different components. I will also explain how you can build a 1.5W PA transmitter. The project will include PCB

100Khz Crystal Calibrator -  There is a great deal of old amateur gear which many amateurs have decided to restore and bring back to life. While much of the early amateur transceivers work just fine they usually lack a digital readout and must rely on analog dials for tuning. The problem of dial calibration is complicated by the non-linear effects of tuning capacitors.  This month's circuit is a 100Khz crystal calibrator using an inexpensive microprocessor crystal and CMOS IC's which are readily available at Radio Shack.... [Radio Amateur Society of Norwich]

100W FM Amplifier -  This Power amplifier is equipped with a bipolar transistor, the famous MRF317 As lots of FM amplifier application ,the power transistor is in a C class bias.

10W HF Linear Amplifier -  Electronic circuit design…. [from Harry Lythall's website]

14MHz SSB 10mW Transceiver

150mW FM Transmitter -  Electronic design circuit…. [from Harry Lythall's website]

15dB UHF TV Antenna Booster -  This is an UHF band TV antenna preamplifier circuit With 15dB gain to build easily. It is formed based on BF180 UHF Transistor. The first stage is an band pass filter constructed by the C1, CV1, L1, L4, C7 and C3, the second stage is a base-common

15W Fm-transmitter -  Building a good fm-transmitter(88-110Mhz) begins with getting a good schematic. You don't have to understand the precise working of the transmitter to build it. But some basic information won't harm.

175kHz Inductive Pulse Transmitter -  This circuit is discussed in more detail  in the Experimenters Journal. The transmitter’s six inch diameter coil launches powerful magnetic 175KHz ring pulses that can be detected by the circuit below.... [Designed by David A. Johnson]

1GHZ Frequency Meter -  This is 1GHz frequency counter with 100KHz resolution. Meter is built in around PIC16F84A microcontroller and SAB6456 / U813BS prescaller.

1W Linear FM Booster -  This RF Amplifier is used for boosting small fm transmitters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More voltage can boost the distance but the transistors will be burned much earlier than usual.! In any case do not exceed the 15Volts. The Amp offers 15 dB in the area of 80Mhz to 110 Mhz. L4, L5, and L6 are 5mm diameter air coils, 8 turns, with wire 1mm wire diameter.

1W Portable PLL transmitter -  This small FM transmitter includes a limiter, a microphone amplifier and a PLL digital tuning. All the parts are placed on one circuit board. The RF power is switchable between 1W and 0,2W....

1W RF Power Amplifier for iPOD Stereo FM transmitters -  This map, armored also enables automatic MONO / MPX through a low-pass filter, even with a multiplex on its entry by using an ON / ON, panning, the whole spectrum MPX more RDS is sent to the synthesizer, on the other hand when it is in a position MONO, the low-pass filter is activated and share its cutoff frequency at 15 KHz, only modulation G + D is sent to the synthesizer, as 19 KHz. 19 KHz carrier, the signal multiplex and subcarrier 57 KHz is thereby eliminated, which provides ease of use for example in a string of issue relay tuner, if the link between the issuer Departure and receiver re-issue was not of good quality stereo, you sufficient to switch to mono to improve sound quality, you can then connect the RDS encoder at the re-issuer.

2 channel RF remote control -  This RF remote control it runs at 418MHz frequency and support up to 2 channels. It is very safety as the transmitting code is changing every time you push any button (roll-code function)

2 Meter Transmitter -  This project is a simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood) 2200, PYE, Motorola, Tait equipment, to name but four. The frequency of the crystal is not critical as almost any other Xtal for the 2-meter band will function.... [from Harry Lythall's website]

2 Transistor LED Flasher (Bill Bowden) -  This circuit will flash a bright LED (500 mcd) as an attention getting device.

2 Transistor Transmitter (Rob van der Weijden) -  A compact 2 transistor transmitter for use at VHF frequencies.

2 Valve 40m CW Transmitter -  amateur radio construction projects….circuit only, no description given…. [from Peter Parker's website]

2 Valve CW Transmitter -  Electroinic circuit design…. [from Harry Lythall's website]

2.x GHz WiMAX Direct Conversion Transmitter -  AN-826 Analog Devices Application Notes....[App Note]

20W FM Amplifier -  This Power amplifier is equiped with two Philips bipolar transistors : the BLV10 & BLW87. As lots of FM amplifier design, the RF transistors are in a class C bias. The FM amplifier has a 21 dB gain with a 55 to 65% efficiency.

250mW HF CW Transmitter -  Electroinic circuit design…. [from Harry Lythall's website]

25W RF amplifier  -  RF amplifier with 25W of power for 88-108MHz FM transmitters.

27MHz AM/CW Transmitter -  Electroinic circuit design…. [from Harry Lythall's website]

27MHz toy car receiver - Electrical Engineer, Engineer of Informatics]

27MHz Transmitters -  n this discussion we cover 27MHz transmitters and receivers as found in remote control cars, aeroplanes, walkie talkies and some of the older-style garage door openers. We have provided a number of circuits so you can work out the best type for your application and these circuits will also help you understand which components are critical.

2N2222 40 Meter CW/DSB Transceiver -  In spring of 1998, NorCal sponsored a contest to design and build a project using no ICs and 22 or fewer 2N2222s as the active semiconductor devices. I thought this was a really intriguing idea, so I set about to design my version.

2W RF Amplifier For 24/23 CM -  This page describes TX ATV Transmitter for 23 cm with output adjustable from 100 to 250mW.

3 Channel IR Remote Control -  This project is a 3-channel IR remote control with 3 output relay and easy to build. Features: CPU PIC12F629 at 4MHz crystal for Tx/Rx, 3 channel output relay, The Tx use sleep mode for saving battery power, Use Phillips RC5 protocol, distance more than 7 m, Easy circuit to build and assembly and small amount of components. Uses RC5 protocol which is probably the most used by hobbyists, probably because the wide availability of cheap remote controls and easy to understand.

3 Channel RF Remote Control -  This is a 3 channel RF remote control project.The transmitter powered by 3V battery(coin size) range about 10 m.  This remote control I use PIC12F509 from Microchip which is a 8-pin single-chip microcontroller designed for low pin count applications with 1 K words flash memory and 41Byte SRAM and some special features such Power-saving Sleep mode,Wake-up from Sleep on pin change.

30 Meter QRP Transmitter for Morse Code -  This transmitters' intended purpose is for morse-code only in  30 meter band (Tony van Roon's 10Mhz).  It is a low-power QRP type and needs to be connected to your existing tranceiver.  harmonic rejections on  prototype were measured at 40dB on 20Mhz and 50dB on 30Mhz.... [Tony van Roon's circuit]

302 MHz Prescaler -  A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range of A Little More Serious Frequency Meter. The MCT10280 prescaler can be set to divide by 80, 40, 20, or 10, as a function of which pins are tied to the power supply. I set this one to divide by 10 since it is adequate for my needs, and the mental calculation of multiplying the meter reading by 10 is not taxing. One problem with the MCT10280 is that if it doesn't have an adequate input, the output is very noisy, which shows up as counts in the couple MHz range on the frequency meter.  This noise shows up if the signal amplitude the signal frequency is too low. For this reason, I only intend to use the prescaler with inputs between 10 MHz and 300 MHz.

303MHz TRANSMITTER with 32kHz Crystal -  We have covered 27MHz (and 49MHz) links on P1 and P2 of this article and shown how to produce a simple circuit (or buy a toy for less than $10.00) and get 4 or 5 channels.
We also showed how to produce on/off from a single channel and how to detect 27MHz with a Field Strength Meter.

30m direct Conversion receiver -  This simple receiver was originally intended to check the transmission of my 30m QRSS beacon. By tuning the 30m receiver to Russia's RWM time signal on exactly 9996kHz I was able to calibrate my frequency counter, which I could then use to measure the output of the QRSS beacon and adjust the reading for a very high precision. Later, I modified my 1-valve ECL82 CW transmitter for 30m operation and enjoyed several QSO's on 30m CW.

30W VHF FM Amplifier for 88-108 MHz with BLF245 MOSFET -  The achievement of this 30-watt amplifier has been designed to take place on a heat sink microprocessor PC equipped with its fans, the advantage of this method of cooling has been selected for the fact that

3m 100 MHz small bug

3V FM Transmitter for 88MHz to 108MHz -  The important part of the circuit is formed of the Colpitts type oscillator. C3,C4,C5,C6,CD1-CD2 and L1 determines the frequency. BF982 and dual gate MOSFET are active parts in oscillator. When the input impedance of the MOSFET gate inputs are high, LC tank is not affected. However transistors force the LC tank and cause phase shift. Two driver stages are added to isolate the antenna from oscillator. First stage (BF199) amplifies the low signal of the oscillator and works as a constant load. The second stage (BFR90) amplifies the signal going through the antenna some more. A short copper wire can be used as an antenna here. Attaching a large antenna to this circuit is unnecessary because the output power is low.

3W FM Transmitter -  This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isn't so bad, a PLL can be used on this circuit.  This is a circuit that I've build a few years ago for a friend, who used it in combination with the BLY88 amplifier to obtain 20 W output power. From the notes that I made at the original schematic, it worked fine with a SWR of 1 : 1.05 (quite normal at my place with my antenna).

3W HF QRP Linear Amplifier -  Electronic circuit design…. [from Harry Lythall's website]

4 Transistor Transmitter -  This circuit provides an FM modulated signal with an output power of around 500mW. The input Mic preamp is built around a couple of 2N3904 transistors, audio gain limited by the 5k preset. The oscillator is a colpitts stage, frequency of oscillation governed by the tank circuit made from two 5pF capacitors and the inductor.... [Design by Paul K Sherby]

40 Meter, 5 Watt QRP Transmitter -  As ham operators, we like to broaden our horizons by trying something new. There is nothing more satisfying about this hobby than building your own transmitter. The circuit in figure 1 is a crystal controlled CW transmitter with at least 5 watts of power. (The prototype generated 7 ½ watts)This circuit was built on a Radio Shack universal board (276-168B) and worked extremely well the first time.... [Radio Amateur Society of Norwich]

400mW VCO FM transmitter -  With good antenna (dipole placed outdoor and high) the transmitter has very good coverage range about 500 meters, the maximal coverage range is up to 4 km.  ....

4-20 mA Digital-to-Process Current Transmitter -  AN-21 Analog Devices Application Notes....[App Note] Describes a 3 I.C. Digital to 4-20 mA Current Output Circuit (DAC08, REF01 and OP221) 

433MHz transmitter using SAW resonator - [Peter Jakab, Electrical Engineer, Engineer of Informatics]

434MHz short-range communications -  article from Elektor 1998/5…. [Peter Jakab, Electrical Engineer, Engineer of Informatics]

4-Transistor Transmitter (Paul C. Sherby) -  This circuit provides an FM modulated signal with an output power of around 500mW.  The input microphone pre-amp is built around a couple of 2N3904 transistors (Q1/Q2), and audio gain is limited by the 5k preset trim potentiometer. The oscillator is a Colpitts stage, frequency of oscillation governed by the tank circuit made from two 5pF ceramic capacitors and the L2 inductor....

5 Channel RF AVR Remote Control -  How many times you needed some remote control to handle some electric device ? many times. There are lot of remote controls like infrared, RF, SMS (like my other circuit) and more. The basic small-range remote controls are 2, Infrared and RF (Radio Frequency). One of the weaks of Infrared is that the signal can not pass the walls. So, if you want to control your garage door, the only way is to use some RF remote control. The circuit (transmitter and receiver) use few components and ordinary (I love few component circuits) . Its easy to build it because you don't have to tune-up any coil or variable capacitor. The RF modules are fix to work in 418MHz area.

5 watt 80 meter QRP CW Transceiver -  A great deal of interest has been generated by my previous design articles, so I decided to go to work on a full blown transceiver design. After several months of work, the ROSE-80 transceiver was born.  This transceiver is similar to other designs but contains some unique differences.

5 Watt FM Amplifier -  This design is a 2 stage amplifier that has about 17db of gain, suitable for an input of 50 to 100 MW. Its basically a Veronica 5 watt vco transmitter, without the vco. The transistors are a 2N4427 and a MRF237. Output power is 2.5 to 5 watts, depending on input drive and dc voltage. At 13.7 vdc with 50 MW of drive, the output was 2.5 watts. The maximum dc voltage recommended is about 15-16 volts.

5 Watt FM Transmitter with Antenna 88-108 MHz -  Two stages -- AUDIO AMPLIFIER AND OSCILLATOR and RF POWER AMPLIFIER 

5 Watt HF CW transmitter -  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, increase the value of Cx. It is Cx which causes the square wave from the output transistor to approximate a sine waveform. The value of Cx is the price of simplicity in this TX.... [from Harry Lythall's website]

5 Watt UHF TV Amplifier -  This small circuit is a Linear amplifier for driving small UHF TV transmitters. Its gain is 7dB and can amplify a signal between 450-800 MHz. You can drive the circuit with 1 to 1,5 Watts signal. Better use double layer PCB with the second layer connected to earth.

500mW HF Linear Amplifier -  Electroinic circuit design…. [from Harry Lythall's website]

5W PLL FM Transmitter -  Easy to build high-quality PLL FM transmitter with typical output power of 5 W and no-tune design…....

5W PLL Stereo Transmitter with LCD -  Here's PLL FM transmitter circuit from china.  This circuit uses the familiar 2SC1971 for final power amplifier stage.

60W Linear Amplifier -  This is a RF Linear amplifier for QRO using power mosfet IRF840 with power out 60 Watts. It's simple all solid state circuit. The IRF series of power transistors.

7MHz QRP Transmitter

8 Channel RF Remote Control -  This is an 8 Channel RF Remote Transmitter and Receiver that will allow to remotely control various electronic projects. RF Remote Control provides 2 latched and 6 momentary outputs that could be used to control your favorite devices such as amplifier, robotic devices, RC cars, computer, home appliances, lamps and many other cool gadgets.

80 Meter DSB Transmitter -  amateur radio construction projects…. [from Peter Parker's website]

800 meter 2400ft range FM transmitter that fits on top of standard 9V battery

807 & 1625 Valves -  data on vacuum tubes 807 and 1625 used in ham radio transmitters. Describes various pin voltages and different operation modes.

8W PLL Stereo Transmitter with LCD -  Very stable FM transmitter based on TSA5511 synthesizer. Frequency is performed with three buttons through PIC16F84 microcontroller. Frequency is displayed on 16x1 LCD.

98-108MHz FM audio transmitter Peter Jakab, Electrical Engineer, Engineer of Informatics

A 2.x GHz WiMAX Direct Conversion Transmitter -  AN-826 Analog Devices Application Notes....[App Note]

A 3m 100 MHz small bug

A Simple FM Stereo Transmitter

A small FM transmitter (SMD)

Achieve simple IR data transmission from a PC’s serial port -  11-Oct-07 Issue of EDN  By transmitting appropriate hex values from a PC's serial port to a pair of IR LEDs, a remote-control IR receiver can enable 38.4-kHz data transmission.... [Design Idea by Andreas Grün, Wedemark, Germany]

ALTOIDS Tin Part 15 Version FM Transmitter -  The transmitter uses 2 MPSH10 (equiv BF494 or NTE229) transistors in a double-ended free-running voltage controlled oscillator (VCO) operating at half the output frequency on each side and combined at L2, which is tuned to the 2nd harmonic of the VCO and covers the 88-108 MHz range. A standard 9 volt battery is used for power and fits inside the tin. The mono audio input circuit is totally passive with 70us pre-emphasis provided and the audio quality is great.

AM DSB Transmitter for Hams -  circuit diagram of simple double side band suppressed carrier (DSBSC) transmitter for hams. Circuit uses crystal oscillator, crystal can be switched for multi band operation......

AM FM Simultaneous Transmitter Using Digital IC  

AM Transmitter -  The circuit is in two halfs, an audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. The tank circuit L1 and VC1 is tunable from about 500kHz to 1600KHz.… [Andy Collison]

AN-146: FM Remote Speaker System -  National Semiconductor Application Note

AN-21: 4-20 mA Digital-to-Process Current Transmitter -  AN-21 Analog Devices Application Notes....[App Note] Describes a 3 I.C. Digital to 4-20 mA Current Output Circuit (DAC08, REF01 and OP221) 

AN232: Low Frequency Magnetic Transmitter Design -  Microchip Application Note Published 14-Oct-02

AN242: Designing an FCC Approved ASK RFPIC™ Transmitter -  Microchip Application Note Published 2-Jan-03....[App Note]

AN-543-Monaural FM Transmitter DSP, 20,641 bytes -  AN-543-MonauralFMTransmitter-Analog Device Application Notes....[App Note]  

AN-543-Stereo FM Transmitter DSP, 26,085 bytes -  AN-543-StereoFMTransmitter-Analog Device Application Notes....[App Note]  

AN-654: Optical Module Development Platform 2.5 GBPS Transmitter with Digital Diagnostics -  AN-654 Analog Devices Application Notes....[App Note]

AN-673: 2-Way Multiplexed LCD Drive & Low Cost A/D-Converter using V/F Techniques with COP8 MicroControllers -  National Semiconductor Application Note....[App Note]

AN-826: A 2.x GHz WiMAX Direct Conversion Transmitter -  AN-826 Analog Devices Application Notes....[App Note]

Antennas for HAM Transmitters -  Describes how to construct various type of antenna for Ham Radio Transmitters.....

ATV Repeater Controllers

Automatic message sender for CB

Automatic Repeater -  Circuit designed by Miroslav Adzic.  This circuit will be of interest to  radio amateur and anyone possessing two radios, (one of which must be able to transmit i.e. a transceiver). It is a self powered (audio derived) repeater circuit for receiving a signal and re-transmitting it via  or radio.

Automicro TM02 high power transmitter module schematic - [Peter Jakab, Electrical Engineer, Engineer of Informatics]

BA1404 HI-FI Stereo FM Transmitter  -  The above FM transmitter design is a result of many hours of testing and tweaking. The goal was simple; to test many existing BA1404 transmitter designs, compare their performance, identify weaknesses and come up with a new BA1404 transmitter design that improves sound quality, has very good frequency stability, maximizes transmitter's range, and is fairly simple for everyone to build. We are happy to announce that this goal and expectations have been met and even exceeded.

BandPass Filter -  This band pass filter is in fact a combined high- and lowpass filter. The first stages are a high pass (f>70MHz) and the last stages a low pass (f<180MHz). The lost of this filter is several watts when driven with 20[Watts], but the output signal is (when adjusted with a spectrum analyser) very clean.

Basic RF Oscillator #1 -  This basic circuit is eash to build and the components are not critical.  Most of them can be found in your junk parts  box…. [Tony van Roon's circuit]

Beeper bug transmitter for fox hunt & vehicle tracking

BH1415F FM Stereo PLL Transmitter -  This is FM PLL Stereo based BH1415F IC from Rohm, it's has built in PLL and Stereo Encoder. You can download the schematic, pcb layout and Hex code. The transmitter menu display with LCD, and this have step 100Khz, 200Khz,....1000Khz and have Mode menu (stereo/mono). In Action, LCD Display can solder directly on the bottom.

BH1415F FM Stereo PLL Transmitter -  This is FM PLL Stereo based BH1415F IC from Rohm, it's has built in PLL and Stereo Encoder. You can download the schematic, pcb layout and Hex code. The transmitter menu display with LCD, and this have step 100Khz, 200Khz,....1000Khz and have Mode menu (stereo/mono). In Action, LCD Display can solder directly on the bottom.

BH1417 PLL Stereo Transmitter  -  This is the latest BH1417 FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter, stereo encoder, low pass filter, PLL rock solid frequency transmission and RF output buffer.

BH1417 Stereo PLL FM Transmitter -  The new FM Stereo Micro mitter is now crystal-locked which means that the unit does not drift off frequency over time. In addition, the distortion, stereo separation, signal-to-noise ratio and stereo locking are much improved on this new unit compared to the earlier designs. The specifications panel has further details....

0.1 - 3.5GHz Prescaler -  This handy prescaler divides input frequency by 1000. It takes maximum input frequency of 3.5GHz and converts it into 3.5MHz that may be measured using standard frequency meter.

0-500MHz PIC16F876 RF Power Meter -  RF Measurement has been an expensive work so far the cost of measuring instruments are concerned. RF Meter is based on PIC16F876 microcontroller, AD8307 and 2x20 LCD display. Full documentation is included.

1 Valve CW Transmitter -  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... [Written by Hans Summers]

1 Watt Four Stage FM Transmitter -  This FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier built around transistor BF200 (T2), a driver built around transistor 2N2219 (T3) and a power amplifier built around transistor 2N3866 (T4). A condenser microphone is connected at the input of the oscillator.

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