For all of the following tests, we used a high quality signal generator from BlackStar. The PicoScope trace below shows a pure 1 kHz tone from the signal generator. Please note: although the screenshots below show the THD, SFDR and SINAD measurements in a separate window these are now included within the PicoScope program and are displayed in the
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main window ( see an example ). The diagram below shows a basic power amplifier circuit. The output stage shown is the simple and widely used emitter follower topology. The following tests show how the quality of the signal from output stage can be monitored. Modifications can then be made to the circuit and any improvements recorded. This output stage topology has a stage gain of just less than 1 so it can be easily moved outside the feedback loop as in the circuit below. Initially the circuit was constructed as above. The ADC-216 was connected to point A` in the circuit and the signal generator was connected to the input of the circuit. The PicoScope screenshot below shows the signal at point A`. It is clear that the op-amp is doing a reasonable job as could be expected with such a large amount of negative feedback applied. If we now look at the output at point B`, we can see excessive crossover distortion clearly visible on the scope trace. The harmonic information also indicates the problem with the third harmonic component being the largest of the harmonics. The load resistor connected to point B` was 2k2. It is obvious that the output stage is suffering from severe crossover distortion effects. If we continue to monitor point B but move the output stage inside the feedback loop by connecting the inverting input of the opamp to point B`, we notice a massive reduction in the output stage distortion. Indeed, if you were...
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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