AM radio receivers receive or demodulate amplitude modulated (AM) signals. The most common source of these signals is of course todays Standard AM Radio Broadcast Band but shortwave stations use AM modulation as well. Amplitude modulation was really developed between 1900 and 1917 by amateur radio experimenters (`hams`). Then when WW1 ended, comme
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rcial AM radio broadcasts began. Amplitude modulation means that the output power of a radio stations transmitter increases or decreases in accordance with the music or voice that is being transmitted. If we string out a length of wire, some of that transmitted energy will cause a small current to flow in our wire. That current will increase and decrease in step with the modulation of the carrier wave and if we hook the wire to a diode detector, the detector will detect or demodulate the signal leaving only the audio. The loop antenna is made out one piece of 1X2 pine lumber 6 feet long. Cut the piece in half so that each section is now 3 feet long. Find the center of each and cut a slot the exact width width of the narrow dimension (3/4") on both sections the cut should extend down half way through the piece on each. Now slide and tap the two sections together to form a "X". You may want to glue the two together. Insert two small wood screws side by side near the center of the "X" on one of the cross arms. This will be the starting and ending points for the wire that is wound around the outside of the "X" forming the main antenna. Now insert two more wood screws on the oposite side of the first two. This will be the starting and ending points for the single turn loop of wire that couples the main loop into the radio. Starting at one of the two side by side screws, wrap the wire around the screw a few times to hold it and...
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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