Telephone in-use indicator
Posted on Mar 3, 2013
Related Circuits
New Circuits
-
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.....
.
The Astable Multivibrator, which is generally used as a signal generator, is once again used here...
A simple 3-way crossover, intended for triamping Hi-Fi systems. This is a conventional 12dB /...
For frequencies below 20 MHz, a fundamental-frequency crystal can be used and the resonant tank...
This is a Constant Current Source LED Driver, When the LED driver Upper-NPN is driven by a...
The basic problem for me is that gates on a logic circuit appear to be creating power from...
Magnetic tampering technique is done by bringing a high powered magnet in close proximity of the...
This circuit was developed by Luigi Falcone, I1FLC. He uses seven plug in coils covering 3. 0 to...
A simple passive (no power required) circuit to match an antenna to a radio receiver. This will...
This new stereo FM Micromitter is capable of broadcasting good quality signals over a range of...
As shown for the stable sine wave oscillator circuit. In order to obtain stable oscillation, the...
Automatic volume change with the ambient noise control circuit In the set of all car stereos and...
characters left: