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Laser transmitter/receiver - This set of two circuits from the basis for a very simple light wave transmitter. A LASER beam is modulated and then aimed at a receiver that demodulates the signal and then presents the information (voice, data, etc). The whole thing is very easy to build and requires no specialized parts execpt for the LASER itself. LASERs are available from MWK industries. __ Designed by Aaron Cake
Lego Mindstoms IR Link PIC transceiver - I just finished a half duplex serial asynchronous link from a simple PIC circuit to the RCX. it is able to receive codes from the RCX (or Lego RCX remote control) store them in RAM & EEPROM and transmit any IR op-code to the RCX in turn. included in the firmware is a routine that takes any opcode (s) and expand it to the proper IR packet for transmission to the RCX. I'veused the UiRT circuit with a few modifications for the hardware. The UiRT includes a serial port programmer for the PIC 16F84A so you won't need a separate programmer. Here's the website where you can find the programmer. Here are the modifications to get the UiRT to work with the RCX. __ Designed by Lloyd Gordon
Local Oscillator - The local oscillator is based on the Franklin oscillator, that was so popular in the first half of this century. The Franklin circuit used two vacuum tubes, this circuit uses two direct coupled FET's. The inductor L1 is wound on a ceramic former, about 1/2 inch (12.5mm) Dia. You can make a ceramic coil former from an old 1KW electric fire (heater) element. Nick the element with a hacksaw, and break it on a hard surface __ Designed by EI9GQ homebrew radio
Low Power CMOS
RS485 Transceiver - DN39 Design Notes__ Linear Technology/Analog Devices
LTC1387: 5V RS-232/RS485 Multiprotocol Transceiver - DN176 Design Notes__ Linear Technology/Analog Devices
Mains Remote Alert - Beeper and/or LED remotely-operated via mains supply line; Simple circuitry, easy to build units __ Contact Flavio Dellepiane, fladello @ tin.it
Microphone Amplifier and LPF - The USB/LSB carrier oscillators are fairly conventional, common collector Colpitts oscillators. I used BC548 transistors, not because they are particularly well suited to the job, but because I had a few of them in my junk box. The crystal frequencies are chosen to match the SSB filter in your rig (7.7985/7.8015 MHz in my rig.) __ Designed by EI9GQ homebrew radio
MOSFET PA for SSB Tranceiver - 30 Watt PA __ Designed by EI9GQ homebrew radio
MOSFET PowerAmp - DiY high power MOSFET amplifier200 Wrms 8 ohms -350 Wrms4 ohms __ Designed by Edwin Paij
One FET controls LED array - 04/12/01 EDN Design Ideas: White-LED backlights are gaining acceptance because they offer higher reliability and simpler drive circuitry than backlights based on CCFL (cold-cathode-fluorescent-lamp] and EL (electroluminescent] technology. As a result, white-LED backlights are increasingly common in PDAs (personal digital assistants], cell phones, digital cameras, and other portable devices. A design Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA
Passive filters fill the bill at audio frequencies - 02/01/01 EDN Design Ideas: Low-frequency filters, particularly at audio frequencies, usually take the form of active filters. These filters eliminate expensive inductors with windings of many turns. Both analog and digital active filters are most compatible with large-scale integration at the subsystem and system levels. Design by Richard Kurzrok, Queens Village, NY
Post Mixer Amp - SSB Transceiver-Receiver Section: The post mixer amplifier, makes up for the losses in the passive mixer and i.F. port attenuator. The transistor is a 2N4427, if you don't have one, try a 2N3866, 2N5109, on any similar, medium power VHF transistor. The output transformer is 10 turns with a tap at 4 turns. The core is the same, high permeability ferrite ring, used in other parts of this project. The output supplies DC current for the RX/TX switching diodes at the SSB filter input __ Designed by EI9GQ homebrew radio
Remote Alert - Beeper and/or LED remotely-operated via mains supply line; Simple circuitry, easy to build units __ Contact Flavio Dellepiane, fladello @ tin.it
RS-232 Laser Transceiver - Laser based projects used to be expensive, until the development of solid state lasers. This project is designed for the entry level laser experimenter. The circuit allows any two computers with serial (RS-232) communication capability to communicate over 200 meters using a laser beam. A low cost transmitter only circuit is also presented here for use in one way communication and other laser based projects __ Designed by shaunwilson19 @ yahoo.com
RS-232 Transceiver with Automatic Power Shutdown Control - DN30 Design Notes__ Linear Technology/Analog Devices
RS-232 Transceivers for Hand Held Computers Withstand 10kv Esd - DN64 Design Notes__ Linear Technology/Analog Devices
RS485 Transceivers Operate at 52Mbps over 100 Feet of Unshielded Twisted Pair - DN168 Design Notes__ Linear Technology/Analog Devices
RS485 Transceivers Reduce Power & EMI - DN102 Design Notes__ Linear Technology/Analog Devices
RS485 Transceivers Sustain ±60V Faults - DN203 Design Notes__ Linear Technology/Analog Devices
Rx I.F. and Product Detector - SSB Transceiver-Receiver Section: Two silicon switching diodes are used for receive/transmit switching of the input side of the SSB filter. The iF amp is an MC1350P. This device can give more than 60dB of gain at 7.8Mhz. I decided to use a single iF amplifier stage, followed by a relatively high gain AF amp (60dB +). The output transformer is a KANK3334R, with a 100pf capacitor and 5K6 resistor across the primary. __ Designed by EI9GQ homebrew radio
Simple Circuit 40 meters CW QRP Transceiver - This project describes a little QRP transceiver “full legal power” (5 W at 12 V) for the 40 meters band. The RiG may be built in a gradual manner, in fact it is divided in two main modules, or you may also complete only the RX module __ Designed by Francesco Morgantini IK3OIL
Single FET controls LED array - 04/12/01 EDN Design Ideas: White-LED backlights are gaining acceptance because they offer higher reliability and simpler drive circuitry than backlights based on CCFL (cold-cathode-fluorescent-lamp] and EL (electroluminescent] technology. As a result, white-LED backlights are increasingly common in PDAs (personal digital assistants], cell phones, digital cameras, and other portable devices. A design Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA
SSB Tramsceiver, Exciter Board - Now that people are getting married, and having babies on the internet, isn't it about time someone designed and built an SSB rig on the net?. The rig will be built up from various modules, starting with the SSB exciter board. The first prototype board has been built and tested on the bench but not on air. The resulting SSB signal looks good on the scope, and sounds ok on a monitor receiver. __ Designed by EI9GQ homebrew radio
SSB Transceiver, Transmitter Section - For the transmit mixer, I used a simple single ended JFET mixer. The FET is a J113. The inductors are TOKO KANK3334. You can wind your own on TOKO, or similar formers PRI = 18T SEC = 3T. The transformer at the output of the first stage is 6 Turns, bifilar wound on a ferrite toroid, of the same type used for the RX mixer. I used 2N4427's for both stages. The 2N3866 or 2N5109 should also be suitable. Gain is about 30dB, more than enough to bring the 1mW, from the TX mixer, up to several hundred mW. Use a heat sink on both transistors. __ Designed by EI9GQ homebrew radio
SWR meter for 1 to 1300 MHz - A very simple design, cheap to built, does not require adjustment and works well! Depending on specific components and construction technique used, the upper frequency limit will be somewhere between 150MHz and 5GHz! __ Designed by Manfred Mornhinweg
Transceiver to PC soundblaster interface for digital operating Modes (PSK-31, RTTY, SSTV etc) - All three interfaces presented on this page employ galvanic isolation of the transceiver from PC computer. Audio paths are separated by transformers, optocouplers serve to separate the digital paths (PTT and RTTY keying). __ Designed by Aleksander Stare
USB/LSB Carrier Oscillators - The USB/LSB carrier oscillators are fairly conventional, common collector Colpitts oscillators. I used BC548 transistors, not because they are particularly well suited to the job, but because I had a few of them in my junk box. The crystal frequencies are chosen to match the SSB filter in your rig (7.7985/7.8015 MHz in my rig.) __ Designed by EI9GQ homebrew radio
Yaesu FT-897, FT-857 & FT-817 transceiver-PC interface (YFPI) - This interface is used to fully control a transceiver, from a personal computer, when operating digital amateur radio modes (made in January 2006) __ Designed by Bjarke Korsgaard |
