Considering that I had complained of a schematic typo from Siliconix, it is doubly embarrassing that that April 29`s blog held a few schematic typos of my own creation: in the variation on Morgan Jones`s circuit one of the resistor`s values was off by a decade and, more damning, one of the OpAmp`s inputs was reversed. Below, the corrected schemati
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c is displayed. (The 4/29 blog has been updated to reflect these corrections. ) The generic DC servo circuit (shown below) works perfectly as long as the amplifier does not amplify asymmetrical signals and as long as the output stage`s current swings are within in the class-A window of operation. However, once the output stage jumps out of class-A into class-AB operation, the DC servo will see a net DC increase at its inverting input and it will strive to bring the amplifier back into line with its reference voltage, but at the same time the capacitor will begin to charge to higher voltage, which will throw the bias voltage off (negatively) until the input signal subsides enough to let it discharge back to its idle value, as shown in the graph below. The graph above shows the tube`s current conduction in hot pink, the grid bias voltage in blue, and the capacitor`s voltage differential in green. The signal burst excessively charges the DC servo`s capacitor and its output voltage is thrown off the mark by over half a volt (602mV). The principle behind the clipping-style auto-bias circuits is also simple: monitor the tube`s current conduction while it is operating in class-A; ignore its AC conduction beyond class-A, when the tube moves into class-B. The clipping diode shorts to ground error signals greater than its forward voltage. In other words, the clipping diode`s forwards voltage creates a window that extends from 0V to...
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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