Phone Circuits
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The given circuit, when connected in parallel to a telephone, dis- plays the number dialled from the telephone set using the DTMF mode. This circuit can also show the number dialled from the phone of the called party. This is particularly helpful for.... -
A compact, inexpensive and low component count telecom head- set can be constructed using two readily available transistors and a few other electronic components. This circuit is very useful for hands-free operation of EPABX and pager communication. Since.... -
Here is a telephone line vigilant circuit to guard against mis- use of your telephone lines. It monitors telephone lines round the clock and provides visual as well as an audio warning (when someone is using your telephone lines) which can be heard anywhere.... -
H ere is a circuit of an off-line telephone tester which does not require any telephone line for testing a telephone instrument. The circuit is so simple that it can be easily assembled even by a novice having very little knowledge of electronics. A.... -
Very often when enjoying music or watching TV at high audio level, we may not be able to hear a telephone ring and thus miss an important incoming phone call. To overcome this situation, the circuit presented here can be used. The circuit would.... -
Often a need arises for connection of two telephone instruments in parallel to one line. But it creates quite a few problems in their proper performance, such as overloading and overhearing of the conversation by an undesired person. In order to eliminate.... -
In this circuit, a simple calculator, in conjunction with a COB (chip-on-board) from an analogue quartz clock, is used to make a telephone call meter. The calculator enables conversion of STD/ISD calls to local call equivalents and always displays current.... -
The following text describes construction, testing and use of an electronic telephone line simulator of my own design. This self-build project can simulate a telephone call / connection between any two local telephone devices. This for a fraction of the.... -
The circuit consists of a small PIC microcontroller, assembly program, and a few other parts to detect a switch closure from an open door, window, or manual push button and then dial the cell phone number, and transmit a steady tone to indicate the source.... -
Circ?it to close a relay when any phone extension is off-hook. Uoltage at the gate of the MOSFET sho?ld be negative (1-3 volts) with respect to the so?rce then phones are on-hook. Uoltage at the gate sho?ld be positive (8-113 volts) with respect to the.... -
A wonderful diy gsm jammer or cellular mobile phone jammer schematic diagram for use only in GSM1900 with frequency from 1930 MHz to 1990 MHz. The GSM1900 cellular cell phone network is made use of by USA, Canada and most of the nations in South America..... -
The Link circuitry is simple and efficient, employing just two ICs, half a dozen transistors, and a handful of garden variety components. It all runs on 12 volts and is easily assembled. You can have your own home intercom between the kitchen, the garage,.... -
This is the figure simple telephone ring tone generator circuit designed using only a few components. It produces simulated telephone ring tone and needs only DC voltage (4. 5V DC to 12V DC). One may use this circuit in ordinary intercom or phone-type.... -
I know the general rule of world that reading makes man ready, writing makes man everyday but practice makes man perfect. Only theoretical knowledge is not enough for an E. C (Electronics and communication engineering)student. A project is one of the.... -
I am not a great fan of novelty radios, but this one looks swell on the wall and doesn`t take up any shelf space. The Guild "Country Belle" is one of the most recognizable tube novelty radios. Patterned after an old-fashioned wall telephone, this model was.... -
Ever Imagined controlling your home appliances using your cell phone. You can find a lot of circuits for this application. But they make use of Telephone. I modified the circuit and redesigned it to make it compatible with normal cell phone headphone. Just.... -
The telephone ring generator shown generates the bare aerial voltage from a simple switching approach ability accumulation (SMPS) which employs a CMOS Schmitt Trigger aboveboard beachcomber oscillator, 10 mH inductor, aerial voltage switching transistor.... -
The Telephone project posted here is the a telephone ringer which producespleasanttunes when a call is placed to your number. The tunes produced by telephone ringer here are more melodious andsoothing compare to those of old telephone instrument and piezo.... -
MMC corrupt can be caused by damaged MMC or damaged memory card driver. On the Nokia 7610, there is a memory card regulator, it is an integrated circuit and the location is near the memory card connector. Nokia 7610 memory card corrupt can be caused by.... -
Display lights problem on Nokia N73 can be caused by several reasons, for example broken path on the display circuit, damaged the display driver, and others. Here, mobile repair guide provide some pictures relating to Nokia N73 display problem, especially on.... -
Schematic Diagramis a layout of symbols and and connection of every electronic components circuit where serve as a guide on how the circuit function or work. Learn how to read it. At first you might think that it is hard to do so, You are not going to be an.... -
Samsung C3330 Circuit Diagram Download Manual PDF Download... -
Schematic Diagram is a layout of symbols and and connection of every electronic components circuit where serve as a guide on how the circuit function or work. Learn how to read it. At first you might think that it is hard to do so, You are not going to be an.... -
An LED - light emitting diode is used to illuminate keypads keys and LCD screen displays on all mobile phones handsets. It is being controlled by a voltage or current draws on its terminal leds. On schematic diagram we notice that the LEDs is driven by an.... -
This circuit bellow shows a teleremote circuit which enables switching ?on? and ?off? of appliances through telephone lines. Can be used ... -
Cellular phone detector circuit schematic using common electronic parts.. -
This circuit is a circuit diagram of a simple transmitter, but very useful circuit which can be used to transmit telephone conversations. When the telephone receiver on the hook to the line voltage of about 48 volts. R7 preset is adjusted to 24.7 V between.... -
Do you suspect your broadband speed (DSL) is slower than it should be It could be as simple as incorrect polarity in your phone wall socket. Build this very cheap, very simple device to find out whether you need to change your wiring! It might not seem that.... -
The incoming ring is detected by transistor T1 and components wired around it. In absence of ringing voltage, transistor T1 is cut off while transistor T2 is forward biased as resistor R2 is returned to the positive supply rails. As a result collector of.... -
Many of you will have an old mobile phone gathering dust. The circuit shown in this article gives the old mobile a new lease of life, enabling it to switch an electrical appliance on and off in or around the home. The circuit will even talk to you on in.... -
The cell phone shield circuit uses two NE555 timer ICs: One as being a very simple astable multivibrator (IC2) and then the 2nd as being a monostable multivibrator (IC3). The astable multivibrator has timing resistors R1 and R2 but no timing capacitor since....
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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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