This circuit can be used for inductive pick-up elements and dynamic microphones Most soundcards have a line` input and one for an electret (condenser) microphone. To be able to connect an inductive tape-recorder head or a dynamic microphone, an add-on preamplifier is needed. Even in this day and age of integrated microelectronics, a transistorised
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circuit built from discrete part has a right of existence. The preamplifier described in this short article goes to show that it will be some time before discrete transistors are part of the silicon heritage. The preamplifier is suitable for use with a soundcard or the microphone input of a modem. As you will probably know, most sound-cards have input sockets for signals at line level (stereo), as well as one for a (mono) electret microphone. For the applications we have in mind, connecting-up an inductive pick-up element or a dynamic microphone, both inputs are in principle suitable, provided the source signal is amplified as required. The author eventually chose the microphone input on the soundcard. Firstly, because the line inputs are usually occupied, and secondly, because the bias voltage supplied by the micro-phone input eliminates a separate power supply for the preamplifier. The microphone input of a soundcard will typically consist of a 3. 5-mm jack socket in stereo version, although only one channel is available. The free contact is used by the soundcard to supply a bias voltage to the mono electret microphone. This voltage is accepted with thanks by the present preamplifier, and conveniently obviates an external (mains adaptor) power supply. In true transistor-design fashion, the preamplifier consists of three stages. Capacitor C1 decouples the signal received from the microphone or pick-up element, and feeds...
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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