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Loud ringer for phone using KA2411

2016-02-13 10:42  
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This phone is loud ringing tone circuit for generating the electricity bell in the old telephone. This circuit is relatively loud. so can use to replacement the same ringer or the original telephone may be lost. We do not need a new phone.
This circuit is easily to build, because it uses a single IC as shown in figure below.

How this circuit works
The called signal from the telephone lines is entered through C1, R1 Come to the bridge diode circuit D1-D4, D5 is the positive voltage at 20V supply to pin 1 of IC1 thatKA2411orCS8205as theTelephone Bell Replacement IC.
When IC1 is given the supply volt as I said, it will generator a ringing signals through the R5, to drive the Piezoelectric transducer BZ1 be a bell tone out to hear.


The ringing tone light, we may reduce the R5 for low down.
We hear the sound of the Oscillator 2 series, which differ by the output frequency chops to be a frequency generator circuits. Which consists with R3, C3 is low.
F-LOW = 1/1.289 R3.C3
For a maximum frequency is calculated from.
F-h1 = 1/1.504 R4.C4
The second highest frequency is calculated from
F-h2 = 1/1.203 R4.C4

The parts of circuit
IC1__________KA2411 or CS8205___Telephone Bell Replacement IC
D1-D5________1N4007___1000V 1A Diodes
ZD1__________20V 0.5W Zener Diode
R1__________5.6K 1/2W Resistor
R2__________12K 1/4W Resistor
R3__________100K 1/4W Resistor
R4__________390K 1/4W Resistor
R5__________820ohm 1/2W Resistor
C1___________1uF 250V Polyester Capacitor
C2_________10μF 25V Electrolytic Capacitors
C3___________0.22uF 63V Polyester Capacitor
C4___________0.0022uF 63V Polyester Capacitor
C5___________0.1uF 63V Polyester Capacitor
BZ1__________Piezoelectric Transducer

How to builds
All components in this circuit except of the piezoelectric transducers can be assembled into a perforated board. You should check the accuracy. Then try to connect the telephone lines, then call come in, will be have hear the ringing tone, if the sound is not impressive, you can change the RC with formula given above.

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