These two amplifiers are of very good quality, simple and economical in their manufacture. They have two inputs for a 4mV (500KΩ) sensitivity microphone and an input for any 200mV (1MΩ) sound source, that is, the first input is for speech and the second one for the music. These inputs are set with the potentiometers P1 (the microphone) and P2 (sound source). The P3 potentiometer adjusts the tone of the voice. Watching the amplifier circuit of 30W we see that it uses negative feedback, by phase feedback feedback, a part of the output voltage at the input of the acoustic amplifier.
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The push-pull power stage is equipped with two EL34 lamps for 35W or 6V6 for 15W. These lamps are charged from the primary output transformer with an 8KΩ impedance. In the secondary, the power coil includes a feedback coil having about 30 threads of 0.3mm wire, winding 4Ω or 8Ω for the loudspeaker and may also include a high impedance winding of 1.25 ~ 500Ω for the long lines and Speakers operating at 100V.
These amplifiers can be used as follows: The 15W Amplifier for a 20-30W Transmitter and a 35W Amplifier for a 50-70W Transmitter. In this case, the output transformer of the amplifier / modulator has a transformer ratio of 1: 1. The secondary of these 8Ω is connected to the secondary of 8Ω of another output transformer similar to the previous one and the second primary is used in the uplink circuit of the transmitter output light.
In their construction to use wire connections hard 0.6 + 0.8mm with insulation. The wires in the grids have a small length and are remote from any other instrument or connection that could create capacity. To reduce the buzzing at the output from the filaments (alternating heating voltage), insulated twisted conductors must be used to neutralize 50Hz bandwidths.
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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