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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Driving solenoid valve using LM358 as comparator and ULN2003
I'm trying to drive a 12V DC solenoid Valve with following diagram.
In 1st block the PC input is compared with 2.2V and its output goes to block2 and ULN2003 for driving the valve.
The 2nd block is a ...
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ULN2803 relay driver working for high loads
I am trying to understand the working of this Darlington transistor array. I am using it for inductive loads and for driving the loads of my relays, but now I am trying to understand the part of its ...
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What's wrong with this PWM-controlled constant current sink?
T10 gets very hot and starts melting within 30s, even with a heat sink and values way below its rated 15A.
Edit:
I know it is not a true PWM controlled constant current, but that what I can do with ...
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Current mirror: is there a name for this NPN-PNP pair, and how does it work?
I'm looking at the schematic for the MC1460 voltage regulator. At the top it has three current mirrors, each with an NPN-PNP pair. Is there a name for that transistor structure? These pairs look like ...
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Darlington as CB
Why do we use Darlington pair?
I've heard that we don't use it as common base. Why is that?
Why don't we just develop a BJT with high beta value istead of using this structure?
What are the different ...
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DC analysis of Darlington pair
So I'm having this darlington pair here
I'm doing DC analysis of this darlington pair
Can anyone explain why is R2 is 6.58, shouldn't it be aprx 7.39?
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How to localize cause of short circuit in proto board design?
I'm working on a basic application with a microcontroller controlling several components including a:
12V DC pump (Darlington array)
12V PWM fan (Darlington array)
humidity sensor (I2C)
and LED ...
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Is it necessary to opto-isolate a darlington array output?
I've got the following circuit going:
A Vishay opto-isolator (CNY74-4) that takes input from buttons that work on 24V, and outputs to microcontroller pins (an Olimex ESP32-PoE-ISO in my case).
A ...
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Output stage using 2 transistors
I want to understand how does this 2-transistor circuit work. It is used in a schematic for increasing the current rating at the discrete output stage. This does not look like a standard darlington ...
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Darlington array: How to output desired voltage at uln2803a driver colectors?
Someone suggested this driver array to get the current I need:
datasheet
I also need a 12V signal and about a current of 100mA in order to control a relay coil. My 12V signal would come from a logic ...
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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 ...
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Multiple Lamp indicators and LED driving using TPL7407LA simultaneously
I am using TPL7407LA for driver circuit, it will be getting inputs from pic18f67k40 and driving multiple Lamp indicators(24v) and multiple LED indicators(12v).
My question is : Is it possible to ...
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Determine total current in a darlington transistor
I'm trying to figure out what will be the total current consumption of a TIP120.
Looking at the internal schematic I see that the second BJT's base is following the emitter of the first one so it ...
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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 ...
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ULQ2003 not driving a Relay properly
I am driving a 9V DC (5 PINS) Relay from darlington array ULQ2003.
The ULQ2003 COM pin is connected to 9V power supply while the Relay coil is connected to +12V supply. The Ground of both are ...
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Complementary transistor pair with a bipolar transistor and a MOSFET
I own a set of Soviet IN-14 Nixie tubes and I would like to use them to make a vintage clock. I found this example schematic of a "Nixie clock":
I don't understand what is the purpose of using a ...
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Why it is said that second transistor cannot enter saturation mode in Darlington pair?
When I made equations it came out that for both of transistors to be in saturation
Vc-Ve2<.2V
Vc-(Vb2-.7V)<.2V
Vc-Vb2<-.5V ............{eqn a}
As for first transistor to be in ...
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LowPro proportional valve drive circuit clarification
Am new with amplifiers when trying to use them as a current controller so is just after some help in understanding the circuit.
I am designing a circuit that will use a LowPro Proportional Valve ...
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Are there darlingtons more powerful than the ULN2803A?
I made a card controlling 24 electromagnets with an Arduino board via 3 darlington ULN2803A
My power supply for the electromagnets was 20 V and 300 mA for each electromagnet.
Due to the physical ...
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driving a medium power darlington transistor with the output of a 555 timer
Question: What is the limitation on the output of the 555 timer with respect to the requirements of the input of the BDW42G? Can the 555 provide enough current at 5 volts to trigger (sufficiently) ...
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Darlington pair [closed]
Here, the first transistor t1, is to be connected in CC configuration. Doesn't that mean that the collector of the first transistor should be grounded?
Also, the collector doesn't seem to be "common"...
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How can I measure a TIP120's beta?
I was promised a current gain of roughly a thousand. We had an experiment involving this circuit to measure the input base current and output emitter current:
(That base resistor is a 50k ohm ...
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Why is the collector current I_c for a normal common emitter BJT circuit LARGER than that of the Darlington transistor circuit configuration?
I'm a noob to electronics and have been reading up on transistors.
I tried to simulate Darlington (NPN) and Sziklai transistor and compare them against a single common emitter NPN configuration, ...
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Do BJT (Darlington) transistors have a minimum collector current?
I am using a TIP122 Darlington transistor. From the graph provided in the datasheet, I can see that the saturation voltage decreases as the collector current decreases.
Since the load I am driving ...
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Darlington Transistor TIP142 same type but different values
I have a bunch of Darlington NPN Transistors TIP142 that are removed from two separate identical boards. The 1st one have the TO−218 CASE (left side of the image) and the 2nd the TO−247 CASE (right ...
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IR control with Darlington Transistor ULN2003A
I need a simple circuit to control a IR device. I'm quite a newbie with electronics so I would like to know if this circuit is correct because seems is not working.
These are the datasheets of IR ...
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Darlington pair. Purpose of components
Giving the following schematic:
What is purpose of R1 and the diodes ?
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Darlington-pair transistor power amplifier for cd-player
I want to build simple one-transistor power amplifier for cd-player. I found 2sd605 Darlington transistor for it. I use 8 Ohm load speaker and have a lab power supply 20V. I want to connect speaker ...
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Powering 4 modulated IR LEDs through transistor
I've done some research but can't seem to find an answer to my specific problem.
I'm using an Arduino as a beam-break sensor. In order to do that it modulates the IR LED at 38kHz by code and listens ...
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How to get current flowing through the darlington transistor as a switch for a stepper motor?
I have a 17PM-K307-05VS unipolar stepper motor. I am building the driver for the stepper motor. The exact rated voltage and current are unknown, it seems the motor is old or discontinued, but the ...
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Suitable transistors for adaptive motorcycle light project
simulate this circuit – Schematic created using CircuitLab
I am working on something very similar to this, Adaptive LED Headlights – Model 8790 Adaptive 2 as a hobby project.
I have controller ...
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raspberry pi 3 to switch between 2 similar power supplies
I put the following circuit together and it's working fine, but I still want to be completely sure I'm not missing anything. I think I read somewhere that when a relay is used to switch between power ...
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Need help with a 3 stage amplifier
I am working on my final project for class and am STUCK!
I am to design a 3 stage circuit with stage 1 and 2 using a 2N3904 transistor in a votlage divider config. and stage 3 using a darlington ...
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Amplifying signal with Darlington not working
I'm relatively new to electronics and this is not my usual field of work.
For a bigger project I need to read a flow sensor's (Biotech FCH-C-PA-N) output. The output needs to be processed by an ...
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Why Does Flyback Current Destroy Darlington Buffered Op-Amp?
I am working on a project where I'd like to deliver variable DC control voltages to a continuous solenoid motor in order to achieve different velocities of actuation.
To buffer my DC control voltage ...
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Npn transistor failed to work
Sometimes after long time working correctly and turning on and off inductive load, Darlington NPN transistor (ONSEMI BD679) which should follow signal (IN4), fails to work and turns on inductive load ...
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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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uln2003a: Switching ground of device works, however, optional USB function of device doesn't work correctly
I use the uln2003a to switch a device (with use of a MCU) that is capable doing several things, like fm-radio, bluetooth, playing MP3's etc. It also provides an USB ...
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ULN2803a relay connection
A motion sensor and a relay should be connected with an atmega328p. I soldered my circuit on a perfboard and have 5V power and ground rails on it.
Can I use the rail for the COM port of the ULN2803a ...
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darlington transistor led matrix
I want to run an 8x8 led matrix by using a darlington transistor arduino and decoder. for some reference I was looking at this previous question(Darlington Transistor Array). Each of my Leds draws ...
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Why is the load on a darlington pair put before the transistors rather than after?
Forgive my lack of understanding and if this is answered somewhere I have not found, but...
I have seen lots of answers with regard to how to use a darlington pair to switch, say, a 12V 1A load using ...
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ULN2002A Not turning on?
I ordered a few ULN2002As.
I have it wired as follows:
Pin 1 -> GPIO of Arduino Pro Mini 3.3V
Pin 16 -> 300Ω resistor in series with an LED
Pin 8 -> GND
Pin 9 (COM) -> 5V (which is also RAW for ...
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Power loss in an equally distributed parallel solenoid circuit
I have 12 solenoids (12v rated) connected in parallel to two Darlington arrays (ULN2803A). Each solenoid has 88-ohm impedance. The power supply can provide a stable 12V with up to 2A current draw. (...
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Using 2N2222 as level shifter for TIP127: simulation works, circuit does not [closed]
I'm building an H-bridge with complementary Darlingtons, TIP122 and TIP127, as they are cheap and the nearby shop has them (i know about the high power dissipation, it doesn't matter), and i found ...
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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 ...
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NPN vs PNP at H bridges
Lots of different darlington pairs datasheets indicates that NPN are faster(lower rise and fall times), stronger(has a higher Hfe and bigger current maximum) and because of gate source tension, easier ...
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What is this UP 4B2 smd chip in dfn8 case?
Acts probably as a driver to power the motor. There a two of this kind on the board. One burned, the train drives only in one direction.
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Lab supply schematic - negative rail and darlington transistor pair
While browsing the lab power supplies market and watching the price ranges, I've decided that I'd be better off with building my own, since I've got most of the needed parts anyways.
I've searched ...
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Sziklai Darlington Transistor Configuration
I'm building a infrared 38khz emitter and I would like to use 4 or 5 LED in multiples directions.
I found this article, where in the end it shows a Sziklai Darlington schematic and dont use resistors....
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opamp heating in voltage controlled current source
Well, I have a serious problem with heat in my circuit. I was trying to build a voltage controlled current source. Everything went fine in the building process. But when I turn ON the power supply the ...