Electronic phone bell
Posted on Sep 15, 2012
New Circuits
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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..... -
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to....
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Here is the latest and greatly improved TX200 VFO/VCO FM transmitter. The most versatile...
The capacitance between the wire and the probe would form a capacitive voltage divider with the...
Ql is used as an oscillator around 300 kHz. R9 is set so that the oscillator just begins to run....
Invert a signal to drive fets with hard/fast rise and fall times. I was told in another thread to...
40kHZ one ultrasonic transmitter circuit, the F1 ~ F3 three oscillators in the F3 is 40kHZ square...
By adjusting its Adjust pin, output voltage and current can beregulated. VR is placed between the...
This design fulfills these requirements by means of a variable gain microphone preamplifier built...
Despite the need for an IC, this ubiquitous interface between the modulator and audio-video...
Timer start-pulse generator is fast series-transistor coincidence circuit. Slop-gate generator is...
The lower schematic is a pretty standard bidirectional rectifier together with capacitors and a...
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