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The multi-circuit circuit telephone

2016-02-10 19:12  
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This article describes a telephone multifunction circuit schematic. In order to better grasp the principle of combining text, please understand this schematic. This circuit provides a visual indication of on-hook, off-hook, and ringing modes. It can also be used to connect the phone to a cid (caller identification device) through a relay, but also that the use or misuse of the telephone line through the sounding buzzer. In on-hook mode block handcrafted, potentiometer vr1 so adjusted, the base t1 (bc547) is forward biased, thereby cutting off transistor t2  (bc108 ). Adjusted potmeter vr1, ensure that only the green led light instead of red. When the block handcrafted cancellation, the voltage drops to about 12 v DC. When this occurs, the voltage of the transistor t1 's group vertebral - emitter junction conductive level below its cut. Therefore, the transistor pair t2 t3 starts vibrating piezoelectric buzzer starts beeping (s1 switch position). Meanwhile, the leadership in the red color of the light. In on-hook mode, 48 v DC power supply is the maintenance of the entire telephone line. In this case, the color of the lead in the green light, the phone displays the idle state. The value of the resistor r1 can be adjusted for changes in some of led light, not loaded telephone line (through trial and error). In ring mode, the green color of the lights blink in synchronization with the telephone rang. cid can be connected using the relay. The relay driver transistor can be connected via a point as shown in the circuit. Warning against the abuse of using a circuit, the switch can be left in position s1 activated piezoelectric buzzer when someone tried to use the phone line. (When the telephone line is touched, like the telephone off-hook mode handmade pieces.) Two 1.5 v Vcc1 pencil cells can provide power, while a separate power Vcc2 recommended to avoid wearing down the battery. However, a 6 volt power supply can be used with a 3.3 v Zener diode cater to two Vcc2 and Vcc1 supply. The principle is very practical, you can Duokanjibian better grasp this principle again.

Multipurpose Circuit for telephone

Multipurpose Circuit for telephone

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