# Darlington Pair (Easy question answer ASAP)

Discussion in 'General Electronics Discussion' started by electronoobz, Dec 31, 2012.

1. ### electronoobz

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Jan 14, 2012

what's the difference? may i know?? ASAP please answer

2. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

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Jan 21, 2010
Simple difference.

The first circuit turns on a bulb, the second looks like an audio amplifier.

3. ### electronoobz

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Jan 14, 2012
i mean is how they are made darlington pair..

hmm.. so in making an audio circuit (guitar pedal) i should conenct the two emitter in the ground and the two collelctor connected and the first collector connected to the 2nd's base??

4. ### KrisBlueNZSadly passed away in 2015

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Nov 28, 2011
Asking about the difference between those two circuits is like asking about the difference between a spider and a horse.

The first circuit demonstrates a Darlington pair controlling a light bulb. When the switch is turned ON, a relatively small current flows into the base of TR1, and is amplified by TR1 to provide a higher current into the base of TR2, which causes TR2 to conduct enough current to light the light bulb. The two transistors function as a single amplifying element with a high current gain. See http://en.wikipedia.org/wiki/Darlington_transistor

The second circuit is a fuzz box effects unit for a guitar. The two transistors each operate as common-emitter amplifier stages (http://en.wikipedia.org/wiki/Common_emitter_amplifier) but greatly modified by the presence of the collector-emitter diodes, and the two stages are cascaded, i.e. the output of the first stage feeds the input of the second stage. The two transistors operate separately.

Last edited: Dec 31, 2012
5. ### electronoobz

226
0
Jan 14, 2012

oh okay. i thought it was a darlington also.. thanks!!

maybe the author type it wrong..hahahaha

6. ### Harald KappModeratorModerator

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Nov 17, 2011
It helps reading the original post thoroughly, or at least to give us the source of your circuit (also on that page). The author clearly refers to the transistor used as "homemade darlington" and gives this equivalent circuit:

This is what you see in your first circuit, too.

Harald

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