Questions tagged [pullup]
A Pullup Resistor brings a line up to a voltage (Typically VCC), while allowing the line to be pulled low.
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Help understanding simple Arduino circuit from a datasheet example
I'm trying to use a water sensor in a new design, and I don't understand the example circuit that is given in the datasheet, even though it looks very very simple. I must be missing something. Any ...
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How long is it okay for pin to be floating during MCU startup?
I’m using an ESP32-S3 to communicate with a 5V-only LCD module with an i8080 parallel bus interface. To shift the levels, I’m using the SN74LVC8T245 bidirectional level shifter. This means I can both ...
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How to bias an input AC signal for active high-pass filter?
I have been trying to design a 2-way active crossover, with low-pass and high-pass channels.
So far I got the desired frequency response but the transient response is not up to mark.
Here is the ...
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Weird I2C Problems
So, currently we are having problems with the I2C Communications on our cabinet Each row on the cabinet has 5 boards which have 2 16bit io expanders each board has 32 devices and there are 4 boards in ...
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GPIO trigger and correct pull-up/-down resistors? Internal pullup deviates from recommended value
I have these devices:
Sensor Keyence FS-N41P
Camera Flir Blackfly S
Controller Teknic Clearcore
The sensor triggers the camera and the controller.
The controller supplies 24V to the sensor.
This is ...
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What types of outputs apart from Open Drain/Open Collector exist?
I am trying to grasp the idea of an Open Circuit/Open Drain, but I haven't been able to find, which other types of outputs exist ("Closed Circuits", so to speak). It would be helpful, if you ...
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How should I select the ohm values for pull-up and pull-down resistors in a device with a USB Type-C connector used solely for power
Good morning, everyone. I am exploring the transition of the receptacle from a micro USB connector to a USB Type-C. Initially, my plan included implementing both sink and source capacity. However, ...
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Replace micro USB tablet connector with USB C
I'm considering upgrading my dad's old tablet, which currently has a micro USB connector. The issue arises from his habit of frequently misplacing the charger, and I'd prefer not to rely on an ...
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PNP transistor not pulling up completely : what is wrong in my schematic?
I cannot seem to make the schematic below work.
As you will plainly see, the idea is to use the PNP as a switching device for a PhotoMOS (TLP354x).
By switching SW1, Q1's base goes to the ground ...
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ESP32 Boot Mode
I am using ESP32-S3-WROOM-1-N16R2 in my design. In ESP32-S3 development board schematic they connect boot pin GPIO0 with external switch.
The reference image of dev board link is below:
https://dl....
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SCL line Pulled Low all the time
I have made a custom PCB with nRF52840 and Three slave Devices(IAM-20380 Gyro), (ADXL372 Accelerometer), (VCNL4040 Proximity ) Sensors. All slaves are connected to one I2C Bus When I plug only power ...
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How to calculate pull up resistor for Power Good Pin?
I am learning to design buck converter.
And using LM70880-Q1 buck.
There is power good pin is available. I want to make use of this pin. It is a open collector output that goes low if the Vout is ...
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Clarification about leakage current in IC
Datasheets usually specific pin leakage current for digital inputs in the Electrical Characteristics, which is generally in microamperes (µA) range. I understood from different SE posts that the ...
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Why do the I2C pullup resistors in the datasheet differ so much from my calculations?
I´m using the LSM6DSR accelerometer/gyroscope from ST on a project. Looking into the application hints, it suggests using a 10k resistor as pullup for SDA AND SCL:
Since I´m using another slave (...
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Ground detection circuit
I'm designing a circuit containing a button with a pull-up/pull-down logic depending on whether I'm grounding a header. The button triggers a GPIO that will detect if the header is grounded thanks to ...
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