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4 Band Resistor
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Off-line Telephone indicator
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 telephone line may be considered to be a source of some 50 volts DC with a source impedance of...
Phone line audio muting circuit
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 automatically light a bulb on arrival of a telephone ring and simultaneously mute the music system/TV...
Privacy in parallel telephone line
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 all such problems and get a clear reception, a simple scheme is presented here (Fig. 1)....
Telephone call meter circuit
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 local call-meter reading. The circuit is simple and presents an elegant look, with...
Auto-Phone dialer for alarm security system
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 of the call. The circuit uses the pulse dialing system to interrupt the line connection...
Phone line in use drives Relay
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 so?rce (gro?nd) then any phone extension is off-hook. ? high impedance meter is needed to...
GSM CELL PHONE JAMMER SCHEMATIC
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. This cellular phone jammer isn`t applicable for use in Europe, Center East, nor Asia. The GSM
Telephone Ring Generator Circuit
This is circuit that produces a ring generator will ring a telephone once every 10 seconds. The interval between rings can be lengthened or shortened by varying the value of the 1 Mega Ohm of resistor. Here`s the circuit schematic. This circuit is using small power transformer. The 70 volt/ 30 Hz ring voltage is produced from the 120 volt side of
The Link Telephone Intercom Every Home Should Have One!
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, the rumpus room and at your poolside barby` and all for less than $100! The Link intercom
Simple Telephone Ring Tone Generator Circuit schematic with explanation
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 intercom. This is the figure of the circuit; The sound is quite loud when this circuit is operated
Guild Country Belle Telephone Radio (1956)
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 manufactured in large numbers and is still quite common. I bought mine for $35 in a local sh
Cell Phone Controlled Home Appliance circuit
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 connect the your phone headphone jack to the phone and the connections to the circuit as sho
Telephone Ringer Circuit
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 buzzer in the current electronic telephone instruments. The circuit is based on the musica
Nokia 7610 MMC Corrupt Problem Picture Help
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 damaged this regulator. To repair the problem, we can replace the regulator with the new one, o
Nokia N73 Display Lights Problem Picture Help
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 display lights problem. The pictures show you how to make a jumper if there are broken pa
CELLPHONE SERVICE-PHANI BUGUDUR
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 experts and master in cellphone repair as long as you don`t know how to read it. Many among
SAMSUNG C3330 CIRCUIT DIAGRAM DOWNLOAD
Samsung C3330 Circuit Diagram Download Manual PDF Download.
How to Read Cellphones Schematic Diagrams
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 experts and master in cellphone repair as long as you don`t know how to read it. Many amon
How Do LED light bulbs works on Mobile Phone Circuit
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 LED driver chip`s, and an Switching Control circuit that also being packed in a chip. The LED
Phone Line Polarity Checker
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 telephone line polarity is important, since the ring and voice signals sent over telephone
Soft Musical Telephone Ringer by UM66T
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 transistor T2 is at near-ground potential and hence IC1 (UM66) is off. Also capacitor C2 is ch
Remote control by mobile phone
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 reply to predefined commands. The overall complexity of the circuit is greatly reduced by the
Cell Phone Shield with Charger
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 it operates with stray capacitance. Its pins 6 and 2 are directly joined to a safeguarding
Simple Mobile Phone Battery Charger
The 220-240V AC mains source is stepped down to 9V AC by transformer X1. The transformer output is rectified by diodes D1 through D4 connected in bridge configuration and the positive DC source is straightly wired to the charger`s output contact, while the negative terminal is connected through current limiting resistor R2. LED2 operates as being
Telephone Ringtone Generator
Telephone ring tone generator circuit, built with only several components. It generates simulated telephone ring tone and requires 4.5V DC to 12V DC voltage
How to Make a Cell Phone RF Signal Detector Circuit
A simple electronic circuit project is discussed here that may be built by any school student for displaying in a school fair science exhibition. The proposed circuit is a high gain opamp amplifier which detects slightest of RF disturbance that might be created by various electrical systems. Cell phone being the major generator of RF interference
Protection For Telephone Line Circuit
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
FM Telephone Bug
FM Telephone Bug. Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency.
Wireless Telephone Bug
Wireless Telephone Bug. Here`s a neat little project that will allow you to monitor your phone line as soon as your phone is off hook. You can use a regular FM broadcast band radio.
Remote control using telephone
Here is 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
Multipurpose Circuit for telephone
Multipurpose Circuit for telephone. This add-on device for telephones can be connected in parallel to the telephone instrument. The circuit provides audio-visual indication of on-hook,.
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