This circuit may look simple, but that`s because I made considerable effort to simplify the circuit. It requires only a small amount of components and it has low current consumption (15 mA). From the left to the right, this circuit consists of a tranducer, a simple transistor pre-amp, a TCA440 IC that contains an oscillator and mixer, a second-ord
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er low-pass filter and a audio-amp consisting of a LM386 IC. The transducer that is used is a piezo-electric transducer, which is quite sensitive but unfortunately has a relatively limited frequency range. By connecting a coil parallel to the transducer, the response can be broadened somewhat, at the expense of decreasing overall sensitivity. The signal from the transducer is first amplified by a simple transistor stage, consisting of a single BC550C transistor. It is biased for a current of approximately 0. 7 mA. The capacitor from the emitter to ground causes a +6 dB/oct gain slope for frequencies higher than 16 kHz. After this it enters the TCA440 at pin 1. In the TCA440 this signal is multiplied with the signal of a built-in tuneable oscillator. The oscillator can be tuned with the use of the potmeter connected to pin 6, from about 18 kHz to 100 kHz. The potmeter must be connected such that it has the lowest resistance when the wiper is turned counterclockwise. This gives a reasonable linear relation between wiper position and tuning frequency, but means that CCW is highest frequency and CW is lowest. The oscillation frequency is determined by the product of the capacitor between pins 5 and 6 and the resistor going from pin 6 to the positive supply connection. The highest frequency is therefore set by the 1n8 capacitor and the 2k resistor, while the lowest oscillator frequency occurs when the circuit sees a 2k+10k=12k...
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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