This new loop antenna by Graham Maynard is his best design yet and I am proud to be the first to present his work. It uses one, six foot square, six turn loop, and is aperiodic in nature, covering the frequency range 50KHz - 5000KHz. The loop is of a size that can be mounted inconspicuously against a garden fence away from household interferences.
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This new `6x6` design uses the centre tapped loop winding as an input phase splitter. This ensures low distortion push-pull operation. The amplifier also has a low impedance shunt input which maximises gain. These aspects give it a better signal to noise ratio than with a single ended or high impedance amplifier. The amplifier provides a useful gain of 42 - 54dB over its frequency range, see the Bode Plot below. Please note, that the Bode plot is derived for the amplifier circuit ONLY, it is not possible to simulate the characteristics of a six foot square loop. The first MPSA18 transistor on each loop operates in common emitter, the collector being directly coupled to a double emitter follower pair. The circuit has self DC biasing, the emitter of the first BC550C being coupled to the base of the MPSA18 transistor. The network of resistors and capacitors around the base of each MPSA18 transistor tailors the amplifier response to the specified limits. The double emitter follower pair evenly distributes the Class A heat dissipation, and direct feedback in the bias chain, counters temperature drift effects. The output from each amplifier half is fed via a 2:1 tri-filar wound push-pull output transformer, with the output winding sandwiched between each primary half. There is equal but opposite current flow and therefore maximum linearity. The output is isolated, which minimizes earth loop noise injection, either via receiver...
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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