a Pierce `aperiodic` oscillator driving a non-neutralized power amplifier for a multiband Morse code transmitter that requires just one coil and minimum adjustment. And then one day you happen to unplug the oscillator tube only to find that it still works! This page explores that topology, the Boosted Pierc
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e (Figure 1), from its Great Depression beginnings through its canonization as a ubiquitous "glowbug" design that just won`t go away. Fundamental to understanding the circuit is that it`s an aperiodic-anode tri-tet oscillator that uses separate triode and screen-grid (tetrode or pentode) tubes. Figure 1 ” Boosted Pierce transmitter based on the version described by Don Mix, W1TS, in October 1968 CE QST. Some variations use more or less voltage, regulated or not, on the oscillator; some variations include a cathode bias resistor in the final amplifier and some don`t; some key both stages and some key only the final amplifier; this version uses a voltage divider to supply final screen voltage rather than the series resistor used in many versions. All have the same aim: better performance than an oscillator-only transmitter without the fuss and bother of neutralization ”but it turns out that neutralization is well worthwhile for multiple reasons. Test point T allows measurement of the final grid current, with every 0. 1 V across the associated 100-ohm resistor equating to 1 mA of grid current in the 5763 ”a value worth measuring, because underdrive is likely at 7 MHz and higher frequencies in every Boosted Pierce design that does not overstress its crystal. RS1 and RS2 are proportioned to set the screen voltage to 204 V, key down, in my test version. (Schematic symbols [Tubepad] and original Mix "Novice Special" Boosted Pierce...
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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