The driver stage works in the same manner as the class A output stage described previously. However it is only working at a couple of milliamps, so efficiency is not an issue here. The biasing arrangement should be familiar by now. Some sets, including the circuit above, have an extra stage of amplification between the volume control and the drive
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r stage. Such sets will be able to receive weaker stations better and probably produce higher volume or better quality on stronger signals. This would take the total to seven transistors, whereas sets without this stage have six transistors. These are the standard line-ups, and most early MW/LW sets will have either six or seven transistors depending on the model and original selling price. Because the class AB output stage current consumption varies with the signal being amplified, the current drawn from the supply (battery) varies in sympathy. This will cause the supply voltage to fluctuate. We need to prevent these rapid fluctuations from finding their way back to the driver and earlier stages, otherwise they could cause distortion and/or instability. In the circuit above we have a 100uF capacitor (C7) directly across the power supply. This would be mounted close to the output stage and would smooth the fluctuations. The supply to the driver stage biasing and earlier stages in the set is further filtered or decoupled by a 1k-ohm resistor (R13) and another 100uF capacitor (C5). If this capacitor fails the set will probably make a horrible noise known as "motor-boating" because it resembles the sound of an outboard motor. If the 100uF capacitor directly across the power supply were to fail the same effect would probably occur but only as the battery starts to run down. The main problem with the two-transformer circuit...
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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