A phase-shift audio oscillator with excellent distortion characteristics thanks to `softened` diode limiting provided by the 1N914 and resistor divider and degenerated gain provided by the 68 ohm emitter resistor. For minimum distortion, increase the 68 ohm resistor to a point just below where oscillation stops. A simple buffer may be adde
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d for driving lower impedance loads. The output amplitude will be about 5 volts p-p but one of the 1N914`s 10k divider resistors may be changed for a different output amplitude. The circuit will work well with a power supply voltage other than 9 volts but the 68 ohm resistor may need adjustment. I just finished watching "Track Down, " a movie about the hacker, Kevin Mitnick. In the movie, Mitnick steals a bunch of files from a phone company named Nokitel and is looking down the list when one catches his eye. He goes back and opens it. The schematic below is what he sees! Wow, those are some valuable files he has there. I`ve been hacked by a movie about a hacker! I`m not sure how to feel about that. I`ve added a bypass cap and used a different diode symbol since the movie, but it`s mine. In the movie that schematic enabled him to convert his phone into a local scanner. I can`t say I`ve tried it. : ) Too bad it took me 12 years to see this. My 1. 5 seconds of fame is long gone. The circuit can be built in the "blobular cluster" style (to coin a phrase) and potted with epoxy mixed with a little model airplane paint. Use quick-setting epoxy and, holding the circuit by the legs, keep rotating the blob near the end of the cure cycle to get an even coat - quite an art form! The finished module looks quite professional, not unlike many dipped caps. Here is a two-transistor Wien bridge oscillator using an ordinary night-light bulb...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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