Comments on: Transistor intercom circuit.

By: Christiane

Christiane — Wed, 01 Feb 2012 03:06:30 +0000

.hi its me again ,,I have use telephone flat wire for our intercom it is approximately 20m. And my problem is that the sound produce decrease . . .we can here the buzzer but it is not enough to get the attention of the receiver . ..is there any solution to maximize the sound of the buzzer? a loud enough to get the attention of the receiver?, we have 9volts power supply . . i use the bd137 because its the only transistor i found in the market..please help as soon as posible

By: danilyn joy aquino

danilyn joy aquino — Sun, 15 Jan 2012 08:21:40 +0000

hello guyzzz,, what kind of mic will i use???

By: corpuz

corpuz — Wed, 11 Jan 2012 08:36:42 +0000

hi!! can i use any 8 ohm speaker?? what do you think is the most suitable wattage of the speaker i should use?? thank you!! ^^

By: USAMA

USAMA — Sat, 31 Dec 2011 06:15:30 +0000

You can also use B1446 R instead of BEL 187. I made this intercom and it works A1 with this transistor but i do not understand how this works plz anybody who can tell me how this amplifies i have to give presentation for this circuit on 1st january ……… plz thnxx
usama_1s@hotmail.com

By: christiane

christiane — Sun, 25 Dec 2011 04:53:47 +0000

I really appreciated your wonderful response….Seetharaman . . . .thank you very much

By: arc_reactor

arc_reactor — Sun, 18 Dec 2011 00:24:31 +0000

wow! it is a must to really compliment this circuit,;’. it’s vastly great;,’ i made the circuit and im very happy right now’;,;’ thanks circuitstoday’.’ ur d best’,;’ more power to you guys;’,;’

By: Seetharaman

Seetharaman — Thu, 15 Dec 2011 17:38:18 +0000

Hi Christiane you can use 2N1711, 2N2218, 2N2219, SL100, 8050, BD135, BD137, BD139 etc any medium power NPN transistor.

By: Christiane

Christiane — Thu, 15 Dec 2011 06:09:41 +0000

Hoping for your response immediately.. .thank your kindness

By: Christiane

Christiane — Thu, 15 Dec 2011 06:07:54 +0000

can I use other type of Q3? I cant find it in the market . .. they always say its out of stock … . .please any transistor that i can replace BEL187 . . .i,m rushing my project and this circuit is my only hope. . .thanks

By: arc_reactor

arc_reactor — Sun, 11 Dec 2011 09:07:37 +0000

helo sir,.; could you also publish a circuit in relevance with this one a two-way intercom using at least a 5watt ic amplifier. there will be no mics rather, an 8ohm 0.25 watt speaker could act as the pick-up and output at the same time using a dpdt switch,’,’ i think, theoretically, this would be simple an easy to assemble/.,’; thanks very much;l,;