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Ringing Phone Light Flasher - 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 [url]http://www. hut. fi/Misc/Electronics/circuits/telephone_ringer. html[/url]. Notes: 1. You may need to use a lower voltage zener for D1 and D2.2. You can use a regular relay instead of a solid state relay, but the arcing accross the contacts may destroy it pretty quickly.3. Be very sure that you have not accidentally connected 120V to the phone line when building and installing this __ Designed by Aaron Cake Ringing Phone Light Flasher - I have received several emails 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 __ Contact IQ Technologies
Ringing Phone Light Flasher using optocoupler & relay - I have received several emails 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. __ Designed by Aaron Cake
Self-powered phone messenger - I always keep one totally self powered phone (the way they all used to work) in case of a power failure. This device works the same way, taking all of its power directly from the phone line. __ Designed by Luhan Monat-Mesa Arizona
Silicon MW Broadband Amplifier MMIC's 7/20/88 - App Note Doc #918__ California Eastern Laboratories
Simple 7 band eqalizer - Audio graphic equalizers are very common as commercial products (for Hi-fi, car audio and stage use) but circuits for them are very rarely published. I didn't design this one but it's really very simple. The details shown are for a 7 band but the principle can be extended to almost any number of bands - if you can find accurate enough components. __ Designed by Richard Torrens
Simple Circuit Alarm with telephone dialler interface - This is the lowest cost dialing alarm on the market and shows what can be done with an 8-pin microcontroller. The complete circuit is shown below. You cannot see all the features of this project by looking at the circuit - most of them are contained in the program __ Designed by Colin Mitchell, Talking Electronics
Simple Circuit intercom - Perhaps you need an intercom. Maybe you want to be able to communicate with your house from your shed or garage. Or perhaps as in my case some years ago, you are upstairs in your bedroom doing your schoolwork, you want to know when dinner will be ready, and you are too lazy to get up and shout down the stairs to find out. if so, then this simple intercom project is for you. I have made many of these and never had any trouble getting them working. __ Designed by Hans Summers
Simple Circuit Phone Tap - Will record any conversation on any ph1-on same line, the circuit seems to be a bad design because it does not provide proper isolation and has too low DC impedance (can keep you line off-hook all the Time) __ Designed by Aaron Cake
Simple Circuit Phone Tap - This circuit is extremely simple, therefore there is less chance of any problems. it can be placed anywhere on the phone line and it will record any conversation on any phone on that line __ Designed by Derek Tombrello
Simple Circuit Radio Control from Junk - Here we are going to make a simple radio controlled device using supplies from your local dumpster. This project should cost less than a dollar to make. if you spend more than a dollar on this project, you need to dig more. __ Designed by sixmhz @ yahoo.com
Simple Circuit Skype VoIP analog adapter - it’s a very cheap Skype/VoiP interface to your wired or wireless phone. __ Contact C. Järnåker
Simple Circuit speakerphone - Small Loudspeaker is a fun project to do, you can connect it to your Cellphone or Laptop through a 3.5mm audio jack and can enjoy your own loudspeaker. You can also connect it to any device which has a 3.5 mm audio output, like TV, music player, video games etc. We have used LM386 IC to amplify sound, with a few external components.__
Simple Circuit Telephone Test - I have used this type of circuits for quick testing of telephone equipment. This is a quick hack that does not exactly resemble the characteristics of the real telephone network, but is enough for this kind if applications. if you want better simulation, change the resistor to 600 ohm and increase the power supply voltage. And by the way __ Designed by Tomi Engdahl
Simple Circuit Valve Amplifiers - A collection of economical low power amplifier designs using common low cost valves. __ Contact blehack @ yahoo dot com
Simplery for Cellular Telephone/Camera Flash Illumination - AN95 Linear Technology This publication concerns implementation of high quality "Flash" illumination in cellular telephones/cameras. Performance vs LED based illumination is discussed and flashlamp operation reviewed. Considerations for support circuitry are given, and a practical circuit, accompanied by performance data, __ Linear Technology/Analog Devices
Simulate signals for telecomm tests - 9/11/98 EDN Design Ideas: NOTE: FILE
has several circuits, please scroll to find this one. The circuit in Figure 1 is a miniature gadget that is heLPFul in telecommunication applications. The function of the device is to simulate data flow with predefined patterns and use these patterns to check a cable's or a receiver's functionality. The circuit generates a signal in accordance Design by Samuel Kerem, Patton Electronics, Gaithersburg, MD
Single Cell Flashes White LED - 12/11/03 EDN Design Ideas: Many portable appliances and other products that must operate from a single cell are restricted to working at very low voltages. it is thus difficult to drive white LEDs that typically have a forward voltage of 3 to 5V. The ability Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK
Single-Wire-Telephones for caves & mines - The Single-Wire-Telephone (SWT) has replaced the Army "field telephones" as the weapon of choice for wired cave and mine rescue communications. The devices are very simple, using a single op-amp to both send and receive an audio signal (voice) along a single insulated wire, using the operators coupling capacitance to ground for the return. The receiver has a very high input impedance. Power demand is very low, with many hours (or days) of operation from a 9 Volt battery.__
Small Capacitor Supports Telecom Power Supply During Brownouts - 05/15/08 EDN Design Ideas: By using a charge pump, the energy stored in a small capacitor can support the operation of a "brick" telecom power supply during brownouts Design by Samuel Kerem, Rockville, MD
Smart Phone Light - The circuit shown here is used to switch on a lamp when the telephone rings, provided that the ambient light is insufficient. The circuit can be implemented using just two IC S. A...__ Electronics Projects for You
Soft Musical Telephone Ringer - The normal telephone bell, at times (specially during night when one does not want to be disturbed) , appears to be quite irritating. The circuit shown here converts the loud sounding bell into a soft and pleasing musical tone. __ Contact IQ Technologies
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. . . Circuit by David A. Johnson P.E.-January, 2011
Supervisory Monitors-modem connection - 04/09/98 EDN Design Ideas: (Scroll to find this circuit) in telemetry or security applications in which a modem connection automatically establishes itself between two systems, a failure in one of the systems can interrupt the data exchange while the connection remains established until someone physically breaks the line or restarts the failed system. This situation Design by J Basilio Simies and Jorge Landeck, Instrumentation Center of the University of Coimbra, Coimbra, Portugal
Switched-Capacitor IC & Reference Form Elegant –48 to +10V Converter - 04/24/03 EDN Design Ideas: A system designer must almost always face a trade-off in choosing the right part for an application. The trade-off usually involves performance, price, and function. An example is the issue of powering circuits from a telecom-voltage source. Telecom systems almost exclusively use high-potential negative rails, such as -48V Design by Wallace Ly, National Semiconductor, Santa Clara, CA |
