Vacuum Tubes Valves
Musical & effects
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Metal Detector Circuits
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Human Sensing Circuits
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Optical Sensing Circuits
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AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
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Data Bus Circuits
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RF Converter Circuits
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Video Wall circuits
TV Video Circuits
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8051 / 8052
PCB CAD Software
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555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Cell Phone Charger Using 1.5V Battery
Use this cell phone charger circuit and a 1.5V battery when you do not have main power and need to charge your phone
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 which happens to be the frequency span used for GSM phones. The frequency of operation is set with a trim-capacitor. Ovaj bi do 30 metara, a ovaj drugi bi da mu neko javlja na mail. Ne...
Remote control using telephone
A teleremote circuit which enables switching on` and off` of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls. The circuit described here can be used to switch up to nine appliances (corresponding to the digits 1 through 9 of the te
Telephone line based audio muting and light on circuit
The circuit would automatically light a bulb on arrival of a telephone ring and simultaneously mute the music system/TV audio for the duration the telephone handset is off-hook. Lighting of the bulb would not only indicate an incoming call but also help in locating the telephone during darkness. On arrival of a ring, or when the handset is...
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 conversion of STD/ISD calls to local call equivalents and always displays current local call-meter reading. The circuit is simple and presents an elegant look, with feather-touch operation....
Electronics Telephone Talking Security and other sensors and detectors circuits
Door Phone circuit
Door Phone , LM 386 is just right for a door phone application. It is very useful application in the present urban households. One condenser microphone and a speake..
Cell Phone Operated Land Rover
The basic functions of this drive are to give smooth start to motor change the direction, change the speed etc. Here I am demonstrating one such application of DC drive that will control speed and direction of a DC motor using standard TV remote control. All the standard TV remote controls works on RC5 protocol developed by Philips. So here I am...
Cellphone Operated Land Rover (Mobile Phone Controlled Robot)
CELLPHONE OPERATED LAND ROVER (MOBILE PHONE OPERATED ROBOT). In this project, the robot is controlled by a mobile phone that makes a call to the mobile phone attached to the robot..
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 report that this circuit works well in Australia This circuit is a simple circuit which prevents picking up other telephone when one telephone is in use. This can be done easily
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 telephone company is sending a steady electric current through your telephones. The two telephones, yours and that of your friend, are sharing this steady current. But as you talk into your tele
Telephone ringing circuits
Telephone line surge protection circuits
Telephone line surge protection circuits
Cut Phone Line Detector
Ringing Phone Light Flasher Circuit
How to connect up some lights so that when the phone rings, they flash. This is very useful in a situation were there is lots of noise and it is impossable to hear the phone, such as a workshop. Here is such a device. The ring detect part of this circuit came from
2 line intercom plus a telephone changeover switch
Usually a single telephone is connected to a telephone line. If another telephone is required at some distance, a parallel line is taken for connecting the other telephone. In this simple parallel line operation, the main problem is loss of privacy besides interference from the other phone. This problem is obviated in the circuit presented here. U
9-Line Telephone Sharer
This circuit is able to handle nine independent telephones (using a single telephone line pair) located at nine different locations, say, up to a distance of 100m from each other, for receiving and making outgoing calls, while maintaining conversation secrecy. This circuit is useful when a single telephone line is to be shared by more members resi
Telephone Ring Generator Using Small Power Transformer
The interval between rings can be lengthened or shortened by varying the value of the 1 Meg resistor. The 70 volt/ 30 Hz ring voltage is produced from the 120 volt side of a small 12. 6 VAC power transformer (Radio Shack 273-1365). Both capacitors connected across the transformer windings are non-polarized / 100 volts. Circuit draws about 300mA fro
3.6 Volt cell phone battery meter circuit
This is a similar circuit to the above and provides a 4 LED bar graph indicating the voltage of a common 3.6 volt Lithium - Ion recharable cell phone battery. The reference voltage is provided by a TL431 programmable voltage source which is set to 3.9 volts where the TL431 connects to the 1K resistor. The lower reference for the LED at pin 14 is...
Telephone line monitor circuit
This nifty little circuit lets you record your phone conversations automatically. The device connects to the phone line, your tape recorder`s microphone input, and the recorder`s remote control jack. It senses the voltage in the phone line and begins recording when the line drops to 5 volts or less..
Ringing Phone Light Flasher circuit
You are asking how to connect up some lights so that when the phone rings, they flash. This is very useful in a situation were there is lots of noise and it is impossable to hear the phone, such as a workshop. Here is such a device. The ring detect part of this circuit came from..
Cellular Phone Calling Detector Circuit
This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED. The device must be placed a few centimeters from the cellular phone, so its sensor coil L1 can detect the field emitted by the phone receiver during an incoming call..
Old Phone Intercom
This Photo Instructable shows how to use two old phones as a cheap intercom between Point A and Point B. Might be useful between the house and the sh..
Phone line-powered flashlight
This works in a way that the phone line won`t stay busy while the LEDs are connected and when you pick up the phone, the light goes off and allow you to use your phone normally. hello. u sadi that ur phone delivers 48 v DC n when phone rings, it delivers 96 v AC. right. ! can u plz explain how dis hapend r else send me a link twhich related
Arduino Whole House Telephone Intercom
GPO one-piece telephone
Telephone Technical References
EE-8 Field Telephone
One is in a leather bag and is model EE-8-A. One or more is in a canvas bag and is EE-8-B. All have handsets with the butterfly push-to-talk lever. The -B model does have an original handset and cord. These have been tested in both LB and CB modes and work fine. I replaced the handsets with TS-13`s from Fair Radio summer 2008 because the...
Electronic Telephone Ringer
This circuit produces a ringing sound similar to that made by more recent telephones. It consists of three almost identical oscillators connected in a chain, each generating a squarewave signal. The frequency of each oscillator depends on the RC combination: R4 and C1 around IC1. A, R8 and C2 around IC1. B and R12 and C3 around IC3. C. The pairs...
Protection For Telephone Line
A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically, now that we are hooking up delicate and expensive equipment such as telephones filled with electronics, fax machines, (A)DSL modems
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...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial