Sunday 12 July 2015

How to build a Extended Telephone Ring Amplifier/Repeater Circuit

The talked about phone repeater circuit can increase the range of your land line ring sound from the phone such the particular one has the capacity to make a call heard in another room or perhaps in another house.

The circuit might be associated with an connected buzzer, the buzzer with a driving circuit is then further utilized to expand the range of it. Perhaps a alert light (a light bulb / bulb for instance) when be associated in the event a person with hearing impairment was to utilize in the device. To attain several units it is easy to hook up a lot more than relay output contacts for the specific loads.
How the phone repeater functions:
The signal is obtained straight from the telephone lines. The current from the lines transmits through a set of capacitor C1 and resistors R1, R2, R3 and a rectifier bridge created by diodes D1, D2, D3, D4. Hence a filtered DC signal is accomplished which happens to be then employed on the base of transistor Q1 by means of a positive pulse signal.
The transistor Q1 replies to the rhythmic pattern of the signal acquired at its base, leading to an inverted and amplified signal across its collector resistor. This amplified collector signal is restricted by the set of resistor R5 and capacitor C2 network making certain that the signal is not pulsed rather direct and straight. This modified DC is then placed on the set of Q2 and Q3 transistors hooked up in Darlington configuration for further amplification in order that the final output has the ability to actuate the relay to switch on the buzzer. D5 is employed to safeguard transistors Q2 and Q3 for reverse relay coil back EMFs.


Telephone Ring Amplifier/Repeater extension Circuit


Telephone Ring Amplifier/Repeater extension Circuit
List of components for the offered Telephone repeater circuit
- 2 transistors Q1, Q2: BC547B
- One transistor: Q3: BC337
- Five diodes D1, D2, D3, D4, D5 1N4148
- One capacitor C1: 0.033uF
- 1 electrolytic capacitor: C2: 1uF, 50V
- Two resistors R1, R2: 100K
- 1 resistor R3: 8.2K
- 1 resistor: R4: 180K
- 1 resistor: R5: 39K
- 1 relay (relay) 12V
- 1 12V loud buzzer
Caution: Do not reverse the polarity of the telephone wires to the repeater.


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