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Telephone Line Indicator
With the aid of an (old) moving coil instrument it is very little effort to make a simple voltmeter that, at a glance, indicates the status of a telephone line. Because the input impedance of this circuit is very high, there is no problem in having it permanently connected to the line, since it only draws a tiny amount of current. The schematic sh
If you are lucky enough to have a big house, a large garden, and small children, this project just might interest you. It`s actually a telephone ringer capable of making any mains-powered device work from the ringer of your fixed line. With it, you will be able to control a high-powered siren or horn, as you like, in order to relay and amplify the
Portable phone charger
The phone is a Siemens S65. The official charger that came with the phone says 5V at 420mA. Because these things do not always actually deliver what is printed on them I measured the voltage myself. This is actually quite hard with the tiny contacts on the connector, especially when it also has to be plugged into the phone. Without a phone...
USB phone charger
A portable phone charger for a Siemens mobile phone. Since I don`t use that phone anymore and recent phones can usually be charged with a USB connector I built a new version of the charger. This time with a proper PCB, a USB connector and a higher current capability. Just as the previous charger it is basically just a step-up conve
Mobile Phone diagram
Transmitter Phone FM Transmitter
High Impedance Amplified Telephone Line Tap
This is an amplified telephone line tap, which is designed to be minimally invasive. The interconnect to the phone line has a large input impedance, and is electrically isolated from the main electronics of the circuit. I designed this for use with a DTMF controlled relay driver, which did not come with an interface for direct connection to the ph
MUSICAL TELEPHONE RINGER
The heart of the circuit is IC1, General Instrument`s AY-3-1350 melody-synthesizer IC. IC2 is a TCM1512 telephone ring detector IC that is powered by the telephone line. The circuit`s operation begins when IC2 senses a ring pulse on the telephone line. The detector (internally) rectifies the ring signal and then outputs a voltage to relay RY1 (an
Pulse phone 160168 controller circuit diagram
Pulse telephone 160 168 controller circuit is shown as above, the controller can be installed on the phone or on the switchboard of the trunk. It can effectively prevent the others to freely dail 160, 168. D1 ~ D4 use 1N4004, the rest diode use 1N4008. Q1, Q2 use BT169D; BG1 uses 5401, BG2 uses 9014; Resistor uses 0.125W metal resistor; IC1 is...
Samsung SGH-800 mobile phone logical circuit principle diagram
LOW POWER FM TELEPHONE BUG
Simple telephone time lock circuit diagram
Simple telephone time lock circuit is shown in the above picture. In the circuit diagram, BG1 and BG2 are electronic switches controlled by IC NE555. When the telephone is on-hook, the DC resistance value of the telephone is over 600K?, the current when the external line runs into the IC is very low, and the electronic time lock does not work....
Using an AMI chip P/N S2561, this telephone ringer can be powered line. Audio output is about 50 mW when powered from a 10-V source..
VERY SIMPLE TELEPHONE INTERCOM CIRCUIT
Tro telephones can be used as an intercom by using this circuit. Older style rotary phones that are nonelectronic might work best in this application. Also, handsets only might be powered this way..
Telephone control automatic lighting circuit 1
The diagram shows telephone control automatic lighting circuit. At night, when telephone rings or master takes up telephone transmitter dialing, the light can lighten; when telephone ringer stopped (no one listen) or on-hook, it can delay 10~40s, then the light can die out itself. Moreover, this circuit also set a light triggering button. The ligh
MAX1811 USB mobile phone emergency charger circuit diagram
Solar Powered Cell Phone Charger
The simple circuit below regulates the voltage from a 6v solar panel to a fixed +5v. That voltage can be fed to any cell phone or USB connected portable device, to charge its battery. The circuit uses a Reg113-5 voltage regulator from Texas Instruments. The tiny device can handle up to 400ma of charging current. I would suggest using a solar...
Internal telephone circuit
Internal telephone circuit is shown as below,improving slightly a toy telephone will become a variable practical internal telephone. This phone is compose of the phone component,decoding circuit,ringing circuit and other components. Using more than two the same device parameters telephone connected by wire can constitute internal telephone..
Telephone electronic coded lock circuit
Telephone electronic coded lock circuit is shown as above,the electronic coded lock is suitable for double audio circuits.After the phone adds this coded lock, when you call out,you must use the buttons on the phone to press the four pre-programmed password,then you can make a call.If the password is error, the phone can not dial out. When the...
Telephone electronic ringer circuit
Telephone electronic ringer circuit is shown as above,Figure (a) is the electronic ring circuit with an NPN transistor V1 (choose 9014 or 3DG12) as the core, sound devices YD is also feedback devices composed of the feedback pole and the buzzer equipped with the help of the sound chamber. L1, L2 connect to circuit line;C1 and R1 have limiting...
SMS controller with ATtiny2313 and T10s mobile phone
Wireless Telephone Line Spy
This is a phone bug circuit. This wireless telephone line spy circuit can be used to transmit the phone conversation to a nearby FM radio. This circuit must..
Phone Incoming Call Flasher
This is a circuit of phone message flasher, an alternative way to get alarmed when there is an incoming call. When the phone rings, high line voltage will be..
When a new computer modem enters the household, the demands on the home phone line skyrockets. The Internet surfer can use phone time on a par with the most talkative teenager. And the computer modem user can be quite sensitive about his privacy: simply lifting another receiver can knock him off-line causing emotional stress. The phone wiring
Phone to sound card Schematic
This circuit generates the sound of the electronic ringer found in modern telephones, supplanting the 2-bell electromechanical ringers used previously. The ringing pattern follows the United States convention of 2 seconds on, and 4 seconds off. During the "on" interval, the tone alternates between two selectable frequencies at a rate of 20Hz. Refe
Phone to Microcontroller interfacing with DTMF
How to interface a microcontroller to the phone line. The tones you hear as you enter numbers on your phone can remotely control devices. Learn how to use these DTMF tones in your microcontroller projects. This article was submitted by Mayank Magoo as part of the Hobby parts for articles program. Mayank received a Arduino compatible Modern...
Type C Carrier Telephone Systems
The type C system was first installed about 1925 and has been very extensively used. It incorporates the most desirable features of the systems just considered. Like the type A system, the carrier is suppressed, and hence the effect of line attenuation is minimized. Like the type B, different frequencies are used for transmitting and receiving, an
Telephone Ringer Circuits
Telephone Surveilance Bug Circuits
Ultrasonic distance finder circuit
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 measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
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 find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
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 circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
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 circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
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, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
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 calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
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 supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
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 circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
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 have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity