Questions tagged [darlington]

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

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2answers
751 views

How to avoid NPN leakage current turning on a PNP darlington has high level switch for automotive electrics

I'm new to this forum; I have searched around but can't quite get the answer I need. I am building a kit car and using an Arduino to run all of the electronics. For my power output I am using TIP125 ...
2
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2answers
674 views

H-Bridge with Darlington BJTs, static shoot-through

I have built the following H-Bridge with TIP122 and TIP127 Darlington BJTs: It is made from parts I had around, and I plan to use it for currents up to 2A with a VCC of 12V. Note that 1N4937 diodes ...
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1answer
2k views

Two-stage amplifier

This is my first time designing a circuit by myself :) The input of this circuit is the output jack of my MP3 Player. The output of this circuit is 4-Ohm loud speaker (sometimes I connect 8-Ohm ...
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2answers
3k views

Is it possible to use a ULN2003A Darlinghton array instead of multiple TIP120 transistors?

Looking at the datasheets, I'm not sure their specifics match; TIP127 and ULN2003A My intention is to do something like this, but with the ULN2003A, that I have already: The reason why is that I ...
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2answers
1k views

How do you perform circuit calculations for the darlington pair

I need to know what formulas or set of calculations would be used to figure out the base resistor and load resistors when hooking up a darlington pair as my datasheet for the ds2003 does not provide a ...
3
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1answer
1k views

Help interpreting TIP127 datasheet

I'm trying to build a constant current 2A amplifier using a TIP 127. To be honest, I have a lack of transistor knowledge. I decided to analyze a few existent circuits with a TIP127 and the datasheet. ...
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5answers
1k views

H-Bridge out of 2 (1 PNP, 1 NPN) Darlington Arrays

I need to control, with a µC, 4 single-coil latching relays and I am exploring various options. My first bet would be a H-Bridge. Since H-bridge ICs are quite expensive and are mostly designed to ...
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5answers
759 views

Emulating a switch with open drain outputs

I need to replace mechanical switches with some kind of digital switch. Specifically I want to sent control inputs to various arcade games that use standard JAMMA inputs, which are basically switches ...
3
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3answers
4k views

Any IC similar to ULN2003A with latch or enable/disable?

I'm working on a project that uses a ULN2003A (darlington transistor array) and I need to enable/disable it. The point is that ULN2003A does not have enable/disable pin. I think that a IC with latch ...
2
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3answers
10k views

Use of ULN2003 for LED current drive

I'm trying to use de IC ULN2003 to logically drive the current of different LEDs from a logic input. I have searched for the data sheet but i don't understand how the IC works. I know that there is a ...
2
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2answers
611 views

Difference between SN754410 and ULN2004 [closed]

I am curious about the difference between SN754410 and ULN2004 and what are the specific usages of both? According to data sheets SN754410 is a is a quadruple high-current half-H driver and ULN2004 ...
2
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3answers
1k views

Use Darlington instead of multiple transistors? If so which one?

Using the example half way down a web page titled "Using the BBB to turn on a transistor" I wanted to know if a similar layout could use a Darlington to drive multiple LEDs instead of individual ...
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2answers
2k views

Will utilizing a TIP120 transistor to control the power from 2 9volt batteries in series powering a 12volt fan generate heat? [duplicate]

I want to utilize the below circuit to power a 12volt fan with the components listed. I'm concerned though because when I tried to do this with a resistor, the resistor got -very- hot. I understand ...
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1answer
758 views

Controlling throttle valve with PWM and TIP120

I'm trying to achieve this. He's using a darlington transistor, so I started looking for an appropriate circuit. I've made that, with a TIP120, using a 1k4 resistor (instead of 1k) and a 1N4007 diode (...
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1answer
742 views

Switching a ULN darlington array from TLC5940 driver?

I feel this is going to be a stupid question- TLC5940 is a 16-channel, constant-current sink LED driver. ULN2004A is a high-voltage high-current Darlington transistor array. Since the TLC5940 is ...
3
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1answer
1k views

How to use Darlington arrays to source current in a 7-segment display driver

I'm building a driver for a large common-cathode 7-segment display using a shift register and BJT transistors (more details in this question). I wanted to make it more compact by replacing the ...
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1answer
1k views

Flip polarity on Darlington Tip120

I have an RC Car that I tore apart and I am attempting to rig it to an arduino. The front wheels can turn left and right based on which way the current is flowing and the rear wheels will go either ...
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1answer
2k views

Is it practically okay to use darlington triple?

I need to control a very high current in my project. I'm planning to use darlington formation with three transistors. I'm planning to use BQ24450 to charge a group of 12V acid-lead battery. BQ24450 ...
4
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1answer
1k views

Driving three high power RGB LEDs with PWM, from a 9v battery

I'm building some LED juggling balls. I'm planning to power an Arduino with two AA batteries, and power the LEDs with a 9V battery. I want to drive three of these 3W RGB LEDS in parallel, with PWM. I'...
6
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1answer
304 views

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 ...
1
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1answer
2k views

How to driving small motors using packaged NPN darlington drivers from MCU?

I have this basic circuit of how to drive a motor using a 2N2222 transistor and it all makes sense to me. I found a bunch of cheap ULN2803APG darlington drivers. I am a bit confused on how to wire 4 ...
10
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3answers
8k views

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 ...
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2answers
2k views

Simple amplifier Cuircuit [closed]

I am new in electrical transistors. My project is to make a 1 watt audio amplifier. Can anyone provide a best amplifier circuit using darlington pair and 2N3904 transistor. i searched google. So ...
3
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1answer
2k views

2N3904 Darlington Pair

I am making a amplifier with darlington Pair with 2N3904. In input i used my mobile phone & additional supply of 5 volt. It simulates well in Multisim11 BUT in real the second transistor gets so ...
3
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3answers
3k views

Darlington Emitter-follower used as a buffer

I have a circuit with a Darlington emitter follower used as a buffer between a common emitter amplifier and a low resistance load (speaker). i wanted to know if this arrangement could alone (with the ...
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1answer
2k views

Having difficulties using a darlington (BD681) to drive a 12V fan from an Arduino

I'm trying to power a 12v fan using a darlington so I can control the speed from an Arduino. When I wire up as below nothing happens, even though I'm sending a PWM signal: Circuit diagram http://...