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Build the BASIC SPY TRANSMITTER - Page 1 of 16

Build the BASIC SPY TRANSMITTER - Page 1 of 16
Build the 2 transistor Spy Transmitter Radio frequency projects can seem more difficult than most electronics projects because most of the time you cannot build them on a solderless breadboard and there may be parts used that are not easy to source such as coils and adjustable capacitors. This project is focused towards those who have not yet attempted to build any kind of RF project, and it is laid out in such a way as to make it easy to explore the basic principles of RF circuitry and ensure a successful final product. This simple 2 transistor audio transmitter will send the sounds picked up in a room to any FM radio tuned to the same frequency as the transmitter, somewhere between 80 and 100 Megahertz. Figure 1 - You can salvage most of the parts needed from an old radio Since many of the parts only need to be "close enough", you will probably be able to salvage all that you need from any old radio, TV, or RF based circuit board. You are Viewing... Related:  Electronic Circuits

Mike's Electric Stuff Hobby projects - Simple electronic circuits Computer microphones Learn how to interface electret and dynamic microphones to the standard computer sound card. Metal detectors Theory of operation and schematics of the most common metal detectors used today: Very Low Frequency (VLF), Pulse Induction (PI) and Beat-Frequency Oscillator (BFO). Wireless microphone The wireless microphone transmitter can be built in an afternoon with simple, affordable and widely available parts. AVR projects and AVR Butterfly gcc port by Martin THOMAS G.d.W. SS2010 FHFFM You may like to visit my ARM-Projects page too (projects and information for NXP LPC2000, Atmel AT91SAM7, STmicro STR7, STM32, LMI LM3S and other controllers with an ARM-core). Last update in the ARM-section: 25. Available Projects and Information (Content) "Last updated" may be just additional information not always a new version of a software-package. AVR Butterfly Application code port to avr-gcc Introduction The AVR Butterfly (ATAVRBFLY) made by ATMEL comes with a preloaded application. For german readers: Der Quellcode der auf dem AVR-Butterfly installierten Applikation wird von ATMEL für den IAR C-Compiler zum Download bereitgestellt. Even if you do not own an AVR Butterfly you may find usefull information in the BF application code for general ATMEL AVR development tasks. From the gcc-port of the application code some methodes how to convert IAR-code to avr-gcc/avr-libc-code can be learned. Butterfly gcc-port history Software 2.Oct.2003 - 4.

Operational amplifier applications This article illustrates some typical applications of operational amplifiers. A simplified schematic notation is used, and the reader is reminded that many details such as device selection and power supply connections are not shown. Operational amplifiers are optimised for use with negative feedback, and this article discusses only negative-feedback applications. Practical considerations[edit] Op amp parameter requirements[edit] In order for a particular device to be used in an application, it must satisfy certain requirements. have large open-loop signal gain (voltage gain of 200,000 is obtained in early integrated circuit exemplars), andhave input impedance large with respect to values present in the feedback network. With these requirements satisfied, the op amp is considered ideal, and one can use the method of virtual ground to quickly and intuitively grasp the 'behavior' of any of the op amp circuits below. Component specification[edit] Input bias currents and input offset[edit] When

Circuit Simulator Applet This is an electronic circuit simulator. When the applet starts up you will see an animated schematic of a simple LRC circuit. The green color indicates positive voltage. To turn a switch on or off, just click on it. The "Circuits" menu contains a lot of sample circuits for you to try. Full Screen version. Directions. Standalone (offline) version for Mac, and for Windows. Index of Circuit Examples. More applets. Javascript version. Report a problem/feature request Huge thanks to Iain Sharp for the Javascript port. java@falstad.com

RF Communication Between Microcontrollers – Part I | eXtreme Electronics RF Communication Between Microcontrollers – Part I Jul 07, 2009 Avinash RF 28 In many situations a communication link between to devices becomes essential. This communication can be wired or wireless. IR Communications Used in IrDA, and Remote controls Short Range Requires two devices to be in line of sight. In this tutorial we will learn how to practically implement a wireless link between two MCUs. What is a RF Module ? A RF Module is a small circuit pre built and tested. As you can see they have very low pin count. TX Antenna Vcc (Positive Supply) DATA (Data Input) GND RX Antenna GND GND Vcc (Positive Supply) Vcc (Positive Supply) DATA DATA GND So you just need to apply power and fit an antenna and its ready to work. Go to Part II By Avinash Gupta inShare0

Bipolar junction transistors as switches : Worksheet Question 1: Solid-state switching circuits usually keep their constituent transistors in one of two modes: cutoff or saturation. Explain what each of these terms means. "Cutoff" refers to that condition where a transistor is not conducting any collector current (it is fully off). "Saturation" means that condition where a transistor is conducting maximum collector current (fully on). Notes: In all fairness, not all transistor switching circuits operate between these two extreme states. Question 2: Explain the function of this light-switching circuit, tracing the directions of all currents when the switch closes: Notes: Ask your students to explain what possible purpose such a circuit could perform. Question 3: Trace the directions of all currents in this circuit, and determine which current is larger: the current through resistor R1 or the current through resistor R2, assuming equal resistor values. I'll let you determine the directions of all currents in this circuit! Question 4: Question 5:

Capacitor Voltage Change This curve fitted equation can then be used in LTSpice to model the Y5U capacitor, with its capacitance versus voltage relationship. To model a non-linear capacitance in LTSpice, it's necessary to write an equation relating charge (in Coulombs) versus bias voltage. This mathmatical relationship is written into the value of the capacitor (instead of so many uF or pF) as Q=f(x) where X is the pre-defined variable in LTspice representing the instantaneous voltage across the capacitor. More generally, the charge Q stored in a capacitor is: C(V) is the relationship between capacitance and applied voltage, in this case, as determined by our 7th order polynomial fitted to the measured C versus V data: In a theoretically perfect capacitor of constant value, of course, the relationship between charge and voltage is simple; Q=CV where Q is the charge in Coulombs, C is the capacitance in Farads and V is the voltage in Volts.

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