Telephone Circuits
-
DC voltage present on the telephone line is usually about 45 to 50V, on-hook and off-hook to 6V. The step-down circuit relay is activated. Relay control tape recorder. Audio is.. -
Diodes VD8 ~ VDI1, SCR vs composition control switch main circuit isolation diode VD7, stable orbital tube VD6, simple resistor capacitor C4 constitute buck regulator circuit, .. -
This circuit is used to record telephone conversations on your landline telephone. All you will need is this small circuit and subscription of your PC. There are few times when we forget what we said or told us. So we need recording. Sometime, not many years.... -
Optically isolated phone automatic recording interface circuit, IC3 voice module... -
As shown for the 20Hz signal generator, may be applied to the telephone ringing system, the signal source can also be used for alarm systems and other electronic Used. The circuit is actually a transformer T and a transistor VTl, VT2 composition.. -
The call is made using language chip ISD1016 voice instead of using the phone ringing message controller schematic circuit. The controller can store messages, music, song, or other sounds, as an alternative to monotonous ringing... -
A simple phone automatically shows the recording circuit. In this circuit, after the call Ming sound start switch K is turned on by the sound of automatic message HFC5209D. .. -
A wireless hands-free telephone device circuit diagram as follows: .. -
As shown in FIG later, RTD temperature collected in the field, which was converted into a voltage by the XTR105 voltage is converted into 4 ~ 20mA current output, and then the .. -
As shown in FIG, RTD using Pt100 type thermocouple. When the temperature is 100 ~ 600oC when, XTR105 output current 4 ~ 20mA, RCV420 output voltage of 0 ~ 5V. The figure for th.. -
As shown, collected at the scene RTD temperature, it is converted into a voltage by the XTR112/114 voltage is converted into 4 ~ 20mA current output, and then the twisted pair .. -
Automatic light is introduced by the telephone block system, the phone rang that night and asked the owner to pick up the handset or pull L, the lamp will light up; the phone s.. -
Automatic recording telephone interface circuit as shown, the circuit has an automatic answering and recording function (need to reprovision or small solid state recorder recor.. -
Automatic telephone responder circuit is shown in Fig. FIG IC2 10 seconds voice recording circuit SR9G10A, press the power switch S2, can be built by IC2 electret microphone in.. -
By phone automatically when the lamp base circuit NE555 and optocouplers constituted a call at night, light will automatically light up, hang up delay imi. About, self-extingui.. -
CX9800 models of mobile phones and desktop PC have chosen excellent performance voice processing circuit, the amplitude and bandwidth of the microphone signal is compressed to .. -
Carrier current remote control device or intercom circuit diagram as follows: .. -
Chaolitong Phone Travel Charger for Motorola to 308,328,338 and 368 series mobile phone battery. The charger has a nickel-cadmium, nickel hydrogen, lithium-ion battery switch, .. -
Check loop circuit for automatic telephone answering or tone generator for use reverse automatic repair. .. -
Circuit principle outside into the phone when ringing pulses through C1, R1, D2 to C2 charging voltage in 6V, this voltage causes N1, N2 reverse, V1 analog hook, and start V4, .. -
IC-1 and the associated circuitry form a stable audio tone generator that feeds a buffer amplifier, Ql and Q2. The tone output is taken from the emitters of the transistor pair to supply a carrier voltage for a balanced modulator made up of four diodes—Dl.... -
The XR-T6425 Speakerphone IC makes it possible to carry on conversation without using the handset, while the user is talking into a microphone and listening from a loudspeaker. It is ideal for hands-free conference calls. .. -
The XR-T5995 Speech Network is a monolithic integrated circuit specifically designed for implementing a low cost telephone circuit. .. -
The circuit consists of separate amplifiers—one for each station—rather than a single amplifier and a time sharing arrangement. Ul and U2 are low-voltage audio amplifiers, each of which operates as separate entities with switches at either station.... -
This device consists of a ring detector connected to the telephone line. When the telephone rings, the ring detector impresses high-frequency pulses on the ac power line... -
The XR-T8205 Tone Ringer is primarily intended as a replacement for the mechanical telephone bell. The device can be.powered directly from telephone ac ringing voltage or from a separate dc supply. An adjustable trigger level is provided with an external.... -
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.... -
The device is a dc switch that is normally on via the forward biasing of Ql via R3. Ql now clamps Q2 into a forward state by biasing its complement well into a saturated state via R4. The dc switch is turned off via a negative voltage above that of the zener.... -
A 2N5777 photo-Darlington cell picks up blinking light from the transparent plastic buttons. The power is switched ON and OFF by a hi-beta 2N3904 transistor. The circuit's 9 V battery can be left continuously connected. Less than a micro-ampere is drawn-even.... -
A small neon lamp is triggered into conduction by the telephone's ringing voltage, passes just enough current to activate the LED in optocoupler Ul, which in turn triggers the 6-A Triac that controls 12—a 117-Vac lamp or bell. (Capacitor Cl is necessary.... -
This circuit functions as a line-current sensor and can be connected in series with either of the phone lines. For the circuit to indicate an "in use" status for all phones on a single line, it must be connected in series with the phone line before, or ahead.... -
A large number of intercom stations can be tied together. All units are connected in parallel, and the entire system is buzzed by only one signaling circuit. Each unit is powered individually from 1.5-V cells for redundancy. For greater signal volume, 3-V....
New Circuits
-
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
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.... -
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.... -
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.... -
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.... -
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,.... -
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.... -
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.... -
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.....
Popular Circuits
An IBM PC can operate the two 12-bit A/D converters in Fig. 1 via its printer port. The...
LM4880 is HiFi dual audio amplifier IC from National Semiconductors. This IC is specifically...
The circuit is built around an LM317T adjustable voltage regulator. Its output voltage (VOUT) is...
The internal mute circuit and pre-set gain resistors provide for a very economical design...
One Foot Spot Welder circuit The circuit uses IC CD4541 A precise delay characteristics, to...