Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [darlington]

A structure containing two of the same BJTs, used for increased current gain compared to a single BJT.

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What is this unusual NPN-PNP transistor pair?

I was looking for the datasheet for a transistor I'd discovered during some reverse engineering, a DK52T. Unfortunately I can't find its datasheet, but I found one for the DK52D. See the image below; this is some kind of weird combination NPN-PNP…
parkside
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Is there any reason to use junction or Darlington transistors for power applications?

In quite a few Arduino examples, you see people using junction transistors to power a motor. In this case, for example, he's using a Darlington transistor: http://www.instructables.com/id/Use-Arduino-with-TIP120-transistor-to-control-moto/ Is there…
Dov
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Resistors within a Darlington transistor

I've been considering replacing a 2N3904 and TIP31C with a TIP102 in one of my circuits (PWM LED dimmer), and have noticed in the TIP102 schematic resistors leading from each of the bases to the emitters. My current circuit doesn't have these, and I…
Ignacio Vazquez-Abrams
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BJT power dissipation - Which value to use? (Ta vs Tc)

I'm using a TIP120 (Darlington pair BJT) brought to saturation for a project of mine. I have \$V_{CE(sat)}=1V\$, \$I_C=2A\$, \$V_{BE}=2.5V\$ and \$I_B=0.005\$A, which give me a total power dissipation of: \$P_D=V_{CE(sat)}*I_C+V_{BE}*I_B \approx…
MatLag
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H-bridge failing under load

I have made two H-bridges following this schematic. I have replaced: TIP107 with TIP147 TIP102 with TIP142 The opto-couplers are P785. I have not included the diodes as they are internal to the TIP. I am trying to run two small toy car motors, max…
GiuBu
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What is this triple-transistor arrangement called?

For an old Fuji 2DI200D-100 power transistor module, it uses three transistors internally for each half-bridge: The circuit in question doesn't connect to the middle bases at all, just B1 and B2, so this (dual) triplet is being used solely as two…
rdtsc
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Why are NPN Darlington transistors used to sink current?

I notice that NPN Darlington transistors are commonly used to sink current. Wouldn't it make more sense to use PNP for the purpose? This would avoid shunting the load current through both junctions at once. Granted, we might want to share the…
Sod Almighty
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Darlington Triplet

I was playing around in Falstad Circuit Simulator with powering a 2.5V incandescent lamp with a Darlington Triplet. I tried it two different ways and got slightly different results. I'm not sure if either is technically correct, and I also don't…
Annette Gates
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Push-pull power amplifier on complementary darlingtons

I decided to make a power DC-amplifier. I used complementary darlington pair TIP142 and TIP147. Also TL082 used for negative feedback. The schematic is as below: I gave 100 kHz sine signal and under oscilloscope I noticed the crossover distortion.…
Madras
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Is a darlington constructed with 2 BJTs fully equivalent to an integrated one?

Is a darlington constructed with 2 BJTs fully equivalent to an integrated one? The reason I'm asking is that there are obvious differences, like the collectors which are separated, and also the emitter of one BJT and the base of the other.
amadeus
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What is the use of the PNP transistor in this circuit?

The schematic below describes the structure of a single channel from the 8-Channel Darlington Current Driver TD62783A. Image source: 8-Channel Darlington Current Driver TD62783A I understand most of the circuit's workings but I fail to understand…
Virgil_Tibbs
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Darlington triplet - static electricity detector?

simulate this circuit – Schematic created using CircuitLab I built this circuit. Different versions of this exist on the internet, some using an MPF-102 JFET instead of the 3 NPNs. The various sites describe it in several different ways: "mains…
Annette Gates
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One transistor versus two transistors as a switch

Why does the led dim first and then switch off when I use one transistor as a switch, but directly switch off when I use two transistors as a switch? These are the two circuits:
nsyamimi sazali
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What advantages does the Darlington pair have over the Sziklai pair?

With all the free time I've had lately due to current events, I've found myself looking into analog amplifier design and analysis (if it helps provide context, my area of expertise is power electronics, where we try to avoid amplifying modes…
Hearth
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Why does a 2N2222A Darlington pair have 1/2 the hFE as a single one?

I set up a darlington pair out of 2 2N2222As, each with a DMM hFE of 300 or so, and the resulting hFE is 170. I read on the Interwebs that a Darlington can multiply or add the hFEs of the individual transistors, but this isn't the case (at least…
Compassionate Narcissist
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