Linked Questions

2
votes
3answers
6k views

Why use a resistor for Pull-Up? [duplicate]

I just got my first Arduino and had a question about pull-up resistors. I was trying to connect a push-button to the Arduino at pin 2, and if it's HIGH then I write HIGH to pin 13. Now, in the ...
9
votes
1answer
887 views

Pull Up and Pull Down Resistor Values [duplicate]

I usually use 10K Ohm resistors for pulling up or pulling down micro-controller lines. This is only because I have tons of them. Recently while looking up pick and place surface mount information I ...
1
vote
1answer
2k views

How do you size pull-up/down resistors? [duplicate]

The attached photo is pulled from a Piccolo DSP reference design from TI. They use 57.6k pull-up resistors and 2.2k pull-down resistors to allow configuration of boot pins at startup. I've seen all ...
32
votes
5answers
124k views

How to connect multiple i2c-interface devices into a single pin A4 (SDA) and A5 (SCL) on Arduino?

I want to add a real time clock module into my little project. I want to display both time and date on my existing i2c 2x16 LCD module. Both i2c-interface real time clock module and 2x16 LCD module ...
9
votes
4answers
7k views

What is a push-up/pull-up resistor? [duplicate]

A.S. The question A question on pull up resistors answers only a part of my question as already mentioned in "EDIT" made shortly after this question was asked & answers here (below) are much ...
3
votes
4answers
715 views

Selecting passive components [closed]

I am in the case where I read a lot of datasheet and I quite often see some circuit where the chip manufacturer indicate some value for resistors and capacitor but by not indicating any part number, ...
5
votes
6answers
2k views

What is the function of the resistor in the below circuit?

What is the function of the resistor R13 in this circuit?
8
votes
5answers
2k views

Connecting push button to a controller pin

This problem is decades old but I do not see a direct answer to it on this site. I want the following: This circuit just allows to check the state of the button from inside the micro-controller. ...
3
votes
2answers
368 views

External pull-ups with Atmel microcontrollers: what assumptions can be safely made about the impedance in tri-state mode?

Using an ATmega (the 48/88/168/328 family, if relevant) with a very weak supply, the internal pull-up resistors have proven to draw too much current. The microcontroller is driven at very low clock ...
5
votes
2answers
844 views

How should I alter my PISO shift register circuit so that it works with 3.3v instead of 5v?

I've followed this Arduino guide to build a circuit using a CD4021BE PISO shift register, and 10k pulldown resistors. It works perfectly fine with the Arduino's 5v supply. I then attempted to use ...
0
votes
5answers
238 views

What is the role of resistor in this schematic?

I am a beginner in Electronics and I am not able to understand why do we need to put this resistor(Resistor which comes after the switch) in this schematic? Does it save IC from current? but how ? ...
0
votes
2answers
598 views

Purpose of Pullup Resistor for Active low pins in EEPROM

I am working with a 25LC640A EEPROM, which is having active low control Pins like CS,Hold,wp (Write Protect). I have Connected Pull up Resistor for CS only alone. Its working fine. Please refer the ...
0
votes
2answers
161 views

Open Drain Output to Microcontroller?

I want to check my Li-ion Charger( Microchip MCP73833 ) status with nRF52832. So i will connect Stat 1,2 and PG to nRF But MCP73833 have an open-drain output If i connect pins to nRF without Pull-...
0
votes
1answer
248 views

How does one calculate the resistor in parallel with the MOSFETs?

I would like to know more about the resistors again in parallel with the MOSFETs in the picture. The Si2365EDS is a P-channel transistor and the 2N7002 is a N-channel transistor. How does one ...
-2
votes
2answers
81 views

Digital Design for specified inputs [closed]

I have one input which its states can be 1 or z (high impedance) and the result should be 1 and 0 respectively. Can anyone design a logical function for this? thanks. Edited Part: As you can see the ...

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