Telephone in-use indicator
Posted on Mar 3, 2013
New Circuits
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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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This circuit was inspired by a friend who wanted a reberb for his portable guitar amplifier. I...
This board is designed specifically to control the 5-motor Robot Arm sold by Baycom Technologies....
Converter consists of four quad bistable latches activated in the proper sequence by the digit...
An awful thing happened a few weeks ago. I ran out of telephones to restore. All my payphone...
Our car radio has the annoying habit of forgetting what part of a CD it was playing when you turn...
Why are four legs connected to the green LED and two to the amber LED in the 4017 traffic light...
The ULN2003A and Zener from the driver board inside the same device. It`s a 5 wires motor, but...
The first was interested in a flexible preamp for use with a high-end acoustic guitar with...
Although you don`t find SCR and Triac in all electronic equipment, this does not mean that both...
To obtain such a monitor it`s enough to connect a resistor in series with the bulb and connect at...
Most LED driver circuits use a series resistor to control the current through the LED. For...
AF modulating signal is applied to gates of matched FETs in push-pull through T1 having...
Structure and working principle of this circuit is basically the same as the previous circuit,...
CD4069 unit structure of FIG. 2-5 (a) shown below, it is composed of two abutment surfaces into...
FIG 220V AC by the step-down transformer T, VD3 ~ VD6 bridge rectifier and a three-terminal...
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