This class of amplifier is designed to follow low level stages, one example is a crystal oscillator. An oscillator for optimum performance can NOT be loaded down, it needs an intermediate stage following. This will then present a sufficiently high enough input impedance so it is not considered a significant load to the oscillator. The intermediate
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or buffer stage, while not representing a load must then have a sufficiently low output impedance to drive successive stages. If these concepts of impedance confuse or worry you then look at my other page " what is impedance " it`s a rough and ready explanation, followed by a more technical explanation of impedance matching but hopefully you will come back with a considerably better understanding. From what I said above, two desirable traits of a buffer amplifier are high input impedance and low output impedance. Obviously succeeding stages should also be linear because we don`t want to introduce distortion. As a matter of interest a buffer amplifier is not solely limited to following an oscillator. You could have a requirement of wanting to sample the output of the first mixer for what is called a "Panadaptor", a means of visually seeing adjacent signals on an oscilloscope. Also a high quality agc system should be derived from the last i. f. stage, it should be buffered before going to the agc amplifier and then on to the agc detector. Other examples are low level outputs of audio amplifier stages such as microphone inputs where the microphone is a high impedance type. Although not so common now, phono inputs to audio ampliers also needed buffering. Here I`m going to use a very practical example where one of my readers has a requirement for a voltage controlled oscillator operating at 1. 8 - 2. 0 Mhz (amateur radio band...
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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