Looking at the    On page 32, the datasheet says "The MPU-9250 always operates as a slave device when communicating to the system processor, which thus acts as the master. SDA and SCL lines typically need pull-up resistors to VDD. The maximum bus speed is 400 kHz."  There's no information about what value pull up resistors to use. Doing a quick search on google for mpu9250 schematics I see this schematic   It uses 10k resistors as pull ups. My question is whether this is accurate, and more importantly can I settle for 4.7k resistors since those are what I have lying around?
121881
of the 24LC256 EEPROM states that:     The SDA bus requires a pull-up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz and 1 MHz).   I thought that any resistor with a kΩ value would do the job (and it seems that my EEPROM works fine at different frequencies with a 10 kΩ resistor).  My questions are:   is there a correct value for pull-up resistors ? is there a law/rule to determine this value ? how do different resistance values affect the I²C data bus ?
11237
Currently I have start working on MSP430 Controller and found that there are 4 pins for the supply voltage viz. AVcc, DVcc, AVss, DVss. These are used as analog supply voltage and Digital supply voltage. What are the purpose of providing these twins pins? How can I use these pins during designing of supply section.
47229
What is a decoupling capacitor (or smoothing capacitor as referred to in the link below)?  How do I know if I need one and if so, what size and where it needs to go?    mentions many chips needing one between VCC and GND; how do I know if a specific chip is one?   Would an  4-bit parallel access shift register used with an Arduino need one? (To use my current project as an example) Why or why not?  I feel like I'm starting to understand the basics of resistors and some places they're used, what values should be used in said places, etc, and I'd like to understand capacitors at the basic level as well.
109513
Based on my , since there supposed to be zero voltage (V=IR) drop across a 0&nbsp;Ω resistor, how do we select the  of such a component?  For example, let's say I were to connect a zero-ohm resistor in between 5&nbsp;V power source and a load (circuit variant) which take current ranges from 20-200&nbsp;mA. What is the power rating of the 0&nbsp;Ω resistor I should select?
112307
Are pull-up/down resistors (whether internal or external) only needed for MCU INPUT pins? In contrast, an MCU pin configured as an OUTPUT "knows what level it's at" because it does the driving - a "floating" MCU OUTPUT pin tied to some input of another circuit doesn't make sense, because the state of the MCU pin can only be high or low... do I have this right? Now, upon MCU bootup or failure, it may be beneficial to have a pull-up/down tied to this "MCU output to IC input" line to ensure that the input to some IC is never floating.  Maybe I just answered my own question here... pull-up/down resistors can be used on both input and output pins, depending on application?
22044
Im new in PIC world. I want to ask:  Do I need external pullup resistor for switches and encoders?  When I was using Atmel microcontrollers - I was just turning on internal pullup resistors in software.  In PIC18F25k50 datasheet I found information, that RB port pins are:  "Digital Output or Input with internal pull-up option"  So I assume that some ports may have internal pullups and I have to check datasheet. However I don't know what resistance is there and I can't find it in datasheet.  I'm asking because in many tutorials I see external pullups, so there must be some reason...
105010
I need a second serial async output channel on the MSP430G2553 and would like to use the SPI USCI to do this.  Is the USCI SPI baud rate stable enough to do this at 300 baud, 2400 baud or 9600 baud? I am currently using the 8 MHz clock.  Is there any other option that can save me from bit-banging?  My current thinking for 300 bd Tx is as follows:   set prescaler to 26666 LSB first load byte into Txbuf load 0x7F into Txbuf to generate stop and start bits repeat 2-3 send final stop bits 0xFF   It might also be possible to send ten bits of data on other members of the MSP430 family that contains a SPI.  Thanks for your responses.
92810
I know the basic function of resistors and capacitors. I know filters, oscillators, one-shot,  differentiator/integrator, ADC/DAC, power supplies, etc. But in a motherboard why are there so many external resistors and capacitors? How many of these analog circuits are there? Or does it have something to do with the copper transmission lines?
48372
&ndash; Schematic created using   Will this work as a four-bit shift register? (And by extension a shift register of any size?) Each vertical PMOS / NMOS transistor pair acts as a multiplexer, and the PMOS transistor to its left amplifies the voltage back up to close to V_high. I'd be interested in hearing people's feedback on this. Right now I have only three transistors (and a resistor) per bit. Can I really get it that small a ratio, or are there reasons why I need more transistors per bit?  It's probably worth noting that I don't have master/slave here, so I can only assert (Shift) long enough to move one bit toward the right and no more.  Furthermore, I'm not trying to say that I need a resistor with 100 ohms. That appeared to be the only resistor I could use to make this schematic! What I want is a resistor that has significantly less resistance than the PMOS it's next to when it's at high impedance, but enough resistance to prevent a short circuit from V_high to ground when that transistor is conducting.  Okay, now I've changed each of the BJT's to MOSFET's, and reduced the resistance of each resistor from 100 ohms to 10 ohms. I'm still going on the assumption that (shift) will only be asserted long enough for the gate delays of M4 and M5, and then of M6, so the value of (dataIn) will only make it to M6's output, and won't move to M8 until the next time (shift) is asserted. Is this enough to get this circuit behaving like a four-bit shift register?
96938
i recently assigned for the Powerline Communication project for transmission up to 200MBps.the problem occurred when trying to find circuit for coupling between the modem and the powerline cable.is it just connecting the X2 class capacitor?or is there any special linear transformer for coupling purposes?  thanks....
38601
My PCB design software comes with some libraries that include some common components, like chip resistors and capacitors.  I have noticed, however, that the footprint land pattern for the 0805 resistor is not identical to the 0805 capacitor.  I then did some googling, and discovered multiple IPC standards that don't seem to quite agree with each other.  Is there a reason an 0805 resistor would have a different land pattern than an 0805 capacitor?  Is there a "best standard"?  IPC-7351, IPC-SM-782, or what?
111027
I am thinking about ordering up some parts for every day use. I am thinking about making one big purchase so as to minimize on shipping and other charges.   What are some of the components that any electronics hobbyist should have around ALL the time?  To put a little more scope: typically working with Arduino's, PICs and sensors. 5V - low current projects.   Looking for: component, value or range (if any), manufacturer (optional)   For example -  Resistors, 1K through 100K 5W
7346
I am currently in the process of trying to repair a power supply that has had one of its DC rails fail. A resistor in the PSU has exploded and I am trying to find what value it is.    Band 1: White Band 2: Brown Band 3: Silver (Possibly Grey?) Band 4: Gold Band 5: Green    The weird thing is that the middle band appears to be silver, which should be invalid as far as I can tell. If you assume the silver is grey (although this is unlikely, as there still needs to be a grey colour as well and the band is metallic), it produces a value of resistor which is incredibly uncommon to the point it does not exist (91.8 Ohms 0.5%).  Apologies for the noobie question, I'm just stumped after hours of trying to understand why this is and coming up short :).
118527
What DLNA server program should I choose and how do I set it up? It is an absolute requirement that it doesn't take a lot of resources since it will be running on a 500 MHz machine.  There seems to be quite a few server programs and I don't have any experience with these userfriendly auto-detecet protocols/services.  Btw, the server doesn't have a GUI...
103311
The board I'm looking at is a modem board from a fax machine.  There are 2 identical components labeled VZ1 and VZ2 on the board, both components have F175 on the face and have 2 SMC leads.  One of them has a resistor across the back pins, and they look like they might be part of the power circuitry.
106465
From the product manual / reference guide it looks like SIM900 / SIM900A is already equipped with 12 GPIOs. But could not find information on how to use these GPIOs to control relays directly, instead of routing them through additional MCUs. Most examples on the net (such as ) use the SIM900 just for read/write, completely ignoring its GPIO capabilities. Any pointers on how to use the GPIOs of SIM900 as control signals directly - please help. Thanks in advance.
28697
I have the following circuit, where I put R52 = R53 = 2700 Ohms :    Triggering levels are of 1V and 2V approximately according to my computations, that is okay according to the following figure showing input in green and output in blue :    But what I find really strange is that the maximum voltage output is around 3.3V and not at 5V. How would you explain that ? And last detail : how would you explain that the output is not exactly at 0V when the input is high?  Thank you very much for your help.