This circuit is easy to build and uses standard components available at any Radio Shack store. It accepts the audio tone output of a code practice oscillator or short wave receiver and converts those tones into the DC voltage necessary to operate an old-time telegraph sounder. This lovely set with original shipping box was used for practice only. A small key knob is mounted directly
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on the sounder arm and produces a resounding "click whenever it is depressed. (Same as number 315. ) 3051 * BUNNELL SIMPLE NON-ELECTRIC PRACTICE SET: (12KB) This interesting set was used for practice only. A small key knob is mounted directly on the sounder arm and produces a resounding "click whenever it is depressed. 3053 * BUNNELL ARTICULATED NON-ELECTRIC PRACTICE SET:(15KB) Interesting combination of a brass sounder and telegraph key with a mechanical connection whereby pressing the key causes the sounder to move downward to make a click. It was used to provide practice sounds for people learning the Morse code without the need for batteries and wiring. (Same as item 325. ) 3055 * "AUDIO ALPHABET" MANUAL CODE PRACTICE SENDER:(22KB) This set consisted of a manually operated device which pulled a paper tape past a set of contacts which sensed holes in the tape and sent dots and dashes for code practice purposes. (This unit is in the John Casale - W2NI collection. ) 3060 "OMNIGRAPH" AUTOMATIC CODE PRACTICE SENDER:(41KB) This mainspring-driven Omnigraph was used to key a sounder to provide random morse code characters for practice. It has fifteen code wheels which are notched with dots and dashes and can be shuffled or replaced to provide an unlimited number of combinations of characters. A mechanical speed governor adjusts sending speed. It shifts from wheel to wheel according to settings of "Kicker strips". Key-wound...
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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