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TRF AM Broadcast Receiver - The TRF radio above operates on the AM broadcast band in the range of 550-1650 Khz. it's similar to a crystal radio with the addition of a couple buffer stages and audio amp to drive a speaker. Reception is limited to strong local stations. KFi (Los Angeles) comes in loud and clear at a range of about 7 miles from the 50KW station. __ Designed by Bill Bowden TRF VHF Wireless Data Receiver - This receiver is little more than a crystal set with gain. Operating voltage range spans 3V to 5 V. The one on my bench runs down below 2.5 V. Why TRF? The beauty of this approach lies in its simplicity and lack of critical components. A transistor is used as an RF detector/amplifier, with the emitter and collector at AC ground (no such thing as Miller capacitance here!). All the gain occurs at baseband, and most of that gain occurs in a very inexpensive but good dual op amp. if the LC resonant frequency is pretty close to the transmitter's frequency, it will work. __ Designed by Dick Cappels
Trixie 2 -- Simple Circuit low current DC receiver - low current, junkbox, 40M Band DC receiver __ Contact Vasily Ivanenko
True Linear RF Power Detector - Schematic only __ Designed by va3iul
Tunable IF with TDA7000 - The main motive of the mods was not that the circuit didn't work right, but were several tries to add some kind of frequency indicator to the receiver. The left RCA plug and associated components are witnesses to the last version, adding a FET buffer amplifier and taking signal from the oscillator coil. __ Designed by © John Coppens ON6JC/LW3HAZ
Tuned Radio Frequency (TRF) Receiver - Superheterodyne receivers have been mass-produced since around 1924, but for reasons of cost did not become successful until the 1930s. Before the second world war other, simpler receiver technologies such as the TRF receiver and the regenerative receiver were still widespread. The circuit described here is based on the old technology, but brought up-to-date a__
TV-VCR Light Source 40Khz Repeater - This circuit is designed to be placed directly in front of a standard TV or VCR remote. The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000
2 Meter Converter
- From the article
"Junk-Box Converters for 6 and 2 Meters", by Rod Kreuter,
WA3ENK, QST, January 1997, Page 33. . . . Web Author: David
White, WN5Y
Two Stage Chaotic Colpitts Oscillator for the UHF range - Chaos in the Colpitts oscillator was first reported at the kilohertz frequencies [1]. Later the circuit was investigated in the high frequency (HF: 3 to 30 MHz) range [2, 3]. Chaotic oscillations were demonstrated. __
Two Transistor Reflex Radio - Schematic & PC Board, no circuit description] __ Designed by © David Hoult
Two Watt Amplifier - A 2 Watt audio amplifier made from discrete components. This was one of the earliest circuits that I ever designed and built, in Spring 1982. At that time I had only an analogue meter and a calculator to work with. Although not perfect, this amplifier does have a wide frequency response, low harmonic distortion about 3%, __ Designed by Andy Collison
Two Watt Amplifier - An audio amplifier made from discrete components with 2 Watts audio power into an 8 ohm load. Carlos has used this amplifier on his AM radio for many years. __ Designed by Carlos Feldman
Two Watt Switching Power Supply - in this small switching power supply, a Schmitt trigger oscillator is used to drive a switching transistor that supplies current to a small inductor. Energy is stored in the inductor while the transistor is on, and released into the load circuit when the transistor switches off. The output voltage is dependent on the load resistance and is limited by a zener diode that stops the oscillator when the voltage reaches about 14 volts. Higher or lower voltages can be obtained by adjusting the voltage divider that feeds the zener diode. The efficiency is about 80% using a high Q inductor. __ Designed by Bill Bowden
Two-Transistor Radio - Here is a two transistor radio that really performs! The first transistor acts as a reflex stage similar to the one-transistor reflex radio above except that no RF transformer is used. instead, a 10 millihenry choke sends the RF to the diode detector and the audio to the output stage __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Two-Watt TBA820m AF Amplifier - Here is a simple AF amplifier project based on TBA820M IC . This amplifier can deliver two-watt output power with 8-ohm speaker using a 12V power supply. A 3-16V battery or an AC/DC...__ Electronics Projects for You |
