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Telephone line surge protection circuits – Circuit Schematic
Telephone line surge protection circuits
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Telephone ringing circuits – Circuit Schematic
Telephone ringing circuits
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Telephone interfacing circuits – Circuit Schematic
Telephone interfacing circuits
A telephone uses an electric current to convey sound information from your home to that of a friend. When the two of you are talking on the telephone, the telep...
Telephone privacy circuit – Circuit Schematic
Telephone privacy circuit
Built quickly from the parts found on my home lab, seemed to work on short test with telephone line simulator and line connected to PBX, I have received a repor...
Telephone call meter using calculator & COB – Circuit Schematic
Telephone call meter using calculator & COB
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 con...
GSM Phone Jammer Circuit Schematics – Circuit Schematic
GSM Phone Jammer Circuit Schematics
It is based on NE555 as simple noise-maker whose output is fed to a single transistor oscillator. The oscillator is designed to operate between 800MHz and 2GHz ...
Telephone Ringtone Generator Circuit – Circuit Schematic
Telephone Ringtone Generator Circuit
This is a simple home telephone ringtone generator circuit which is built with applying only several electronic components / parts. It generates simulated telep...
Telephone Status Indicator Circuit – Circuit Schematic
Telephone Status Indicator Circuit
This simple circuit tells you about the status of phone such as Line OK, Dialing and Call attended. It also has a lock facility to block outgoing calls keeping ...
Spy Telephone Circuit – Circuit Schematic
Spy Telephone Circuit
This FM spy telephone circuit is mounted serrial with the phone line. When is signal on the wires this transmitter will radiate airwaves thru the wires wic.....
TBA120 Demodulator Circuit – Circuit Schematic
TBA120 Demodulator Circuit
The TBA120 Series ICs provide a high-gain limiting IF amplifier and a quadrature coincidence detector in one package. These ICs are primarily intended for extra...
Spy Phone Bug Transmitter Circuit – Circuit Schematic
Spy Phone Bug Transmitter Circuit
A very simple telephone broadcaster or transmitter which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless teleph...
Cell Phone Jammer Circuit – Circuit Schematic
Cell Phone Jammer Circuit
A beautiful diy gsm jammer or mobile cell phone jammer schematic diagram for use only in GSM1900 with frequency from 1930 MHz to 1990 MHz. The GSM1900 mobi.....
The Original 2 Phone Link Design – Circuit Schematic
The Original 2 Phone Link Design
This is the circuit that sparked off all the other Link Telephone Intercom designs. Originally designed back in 1996 with heavy duty relays and their contact ba...
Telephone Hold Button – Circuit Schematic
Telephone Hold Button
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DTMF Decoder Using MT8870 – Circuit Schematic
DTMF Decoder Using MT8870
This circuit detects the dial tone from a telephone line and decodes the keypad pressed on the remote telephone. The dial tone we heard when we pick up the phon...
TV audio video transmitter circuit design project – Circuit Schematic
TV audio video transmitter circuit design project
A very simple TV audio video transmitter circuit can be designed using this schematic diagram. This TV audio video transmitter circuit can be used to transmit v...
LM565 FSK demodulator circuit design electronic project – Circuit Schematic
LM565 FSK demodulator circuit design electronic project
A very simple FSK demodulator for the 2025 Hz and 2225 Hz can be designed using the LM565 which is a general purpose phase locked loops IC containing a stable, ...
Cellular phone detector circuit schematic – Circuit Schematic
Cellular phone detector circuit schematic
Using this electronic schematic, can be designed a very simple cellular phone detector circuit which can sense the presence of an activated mobile cell phone fr...
Telephone call meter using calculator & COB – Circuit Schematic
Telephone call meter using calculator & COB
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 calcu...
audio visual ringer circuit diagram – Circuit Schematic
audio visual ringer circuit diagram
Many a times one needs an ex- tra telephone ringer in an ad- joining room to know if there is an incoming call. For example, if the telephone is installed in th...