Circuit
The circuit presented here can be used for connecting two
telephones in parallel and also as a 2-line intercom.
Usually a single telephone is connected to a telephone line.
If another telephone is required at some distance, a parallel
line is taken for connecting the other telephone. In this
simple parallel line operation, the main problem is loss of
privacy besides interference from the other phone. This
problem is obviated in the circuit presented here.
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Doorphone Intercom
A simple 2 way Intercom based on the LM386386 using 8 ohm
speakers.
Doorphone Intercom
A simple 2 way Intercom based on the LM386386 using 8 ohm
speakers.
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High Quality Intercom
This circuit consists of two identical intercom units. Each
unit contains a power supply, microphone preamplifier, audio
amplifier and a Push To Talk (PTT) relay circuit. Only 2 wires
are required to connect the units together. Due to the low
output impedance of the mic preamp, screened cable is not
necessary and ordinary 2 core speaker cable, or bell wire may
be used.
High Quality Intercom
This circuit consists of two identical intercom units. Each
unit contains a power supply, microphone preamplifier, audio
amplifier and a Push To Talk (PTT) relay circuit. Only 2 wires
are required to connect the units together. Due to the low
output impedance of the mic preamp, screened cable is not
necessary and ordinary 2 core speaker cable, or bell wire may
be used.
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Low-cost Transistorised Intercom
The circuit comprises a 3-stage resistor-capacitor coupled
amplifier. When ring button S2 is pressed, the amplifier circuit
formed around transistors T1 and T2 gets converted into
an asymmetrical astable multivib-rator generating ring
signals. These ring signals are amplified by transistor T3 to
drive the speaker of earpiece.
Low-cost Transistorised Intercom
The circuit comprises a 3-stage resistor-capacitor coupled
amplifier. When ring button S2 is pressed, the amplifier circuit
formed around transistors T1 and T2 gets converted into
an asymmetrical astable multivib-rator generating ring
signals. These ring signals are amplified by transistor T3 to
drive the speaker of earpiece.
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Multi-station intercom uses CB microphones
This intercom unit can connect any number of units together,
rather than the limit of two, as with most designs. In practice,
the number of stations required would normally number less
then 10.
Multi-station intercom uses CB microphones
This intercom unit can connect any number of units together,
rather than the limit of two, as with most designs. In practice,
the number of stations required would normally number less
then 10.
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Simple Intercom
Very simple and useful circuit for communication between two
person. The Q1 is used to amplify the weak output signal
of speaker when one push his (her) side push-button to speak.
Simple Intercom
Very simple and useful circuit for communication between two
person. The Q1 is used to amplify the weak output signal
of speaker when one push his (her) side push-button to speak.
This is a very interesting circuit using 2 transistors in each
station to drive a high impedance speaker. 8R speakers will
work quite well and this is an ideal project to connect between
your work-room and the kitchen so you can be told when dinner
is ready!
station to drive a high impedance speaker. 8R speakers will
work quite well and this is an ideal project to connect between
your work-room and the kitchen so you can be told when dinner
is ready!
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STAGE INTERCOM SYSTEM
The intercoms were designed so that they can be added at will to
any part of the link line. The Link is a 2 core 14 strand speaker
cable of pretty standard quality but it provides almost a noise free
connection.
STAGE INTERCOM SYSTEM
The intercoms were designed so that they can be added at will to
any part of the link line. The Link is a 2 core 14 strand speaker
cable of pretty standard quality but it provides almost a noise free
connection.
more
The Ferris Intercom
The movie "Ferris Bueller's Day Off" is a high school comedy
from 1986. It was a rather popular movie at the time and
for years afterward. Anyway, in the movie, there was a scene
where Ferris's high school principle (Mr. Rooney) comes to
Ferris's home and pushes the intercom button. Ferris should
be at home sick, but of course he is out for a day, living it up.
The Ferris Intercom
The movie "Ferris Bueller's Day Off" is a high school comedy
from 1986. It was a rather popular movie at the time and
for years afterward. Anyway, in the movie, there was a scene
where Ferris's high school principle (Mr. Rooney) comes to
Ferris's home and pushes the intercom button. Ferris should
be at home sick, but of course he is out for a day, living it up.
