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H: Circuit component
What is this circular component with two parallel lines in it? I've never seen this before
AI: It is a symbol for DC Voltage. |
H: Contiki: Serial Line IP via SPI
I am working on Contiki's cc2530 port (customizing for my custom radio). I do not unserstand how can i make SLIP work with SPI?
I understand that SLIP is similar to UART (it is UART without parity, what does this mean?), but how can i use it with SPI?
AI: SLIP is a protocol for conv... |
H: V/I uppercase/lowercase convention?
Is there any standard in industry for using uppercase or lowercase for V and I in circuit diagrams? I ask this because my book seems to switch back and forth between the two without any rhyme or reason and I can't figure out any pattern for why it will choose one way over the oth... |
H: Why do we use 32.768 kHz crystals in most circuits?
Why do we use 32.768 kHz crystals in most circuits, for example in RTC circuits? What will happen if I use a 35 or 25 kHz crystal?
I assume because the IC internal Xin, Xout pin circuitry should be in CMOS/TTL/NMOS technology. Is it that true?
AI: The frequency o... |
H: Ethernet Magnetic coil ground
In Ethernet Magnetic part why we using chassis ground and separated choke primary side form common ground?
AI: Ethernet Magnetics are used for providing the isolation between the interface. The reason behind that is the safety and the different potential of linked system. Since the sys... |
H: quick question about AC SPST rocker switch
I'm replacing the motor control switch in this toaster and wanted to be certain about how it should be installed. It's a normal SPST neon rocker switch with A, B and C for terminals, and B-C being for the neon. It would simply be 1-A, 2-B, 3-C, correct?
Hopefully I wasn'... |
H: transformer has continuity but no voltage output?
I have two old transformers that appear to be fine, however no DC voltage was measured on the secondary coil.
I have measured:
The input voltage: 229 AC
the input coil ohms: 0.015 kOhms
the two parallel output coil ohms: 0.008 kOhms each
the multimeter base resista... |
H: Understanding the the setup of a Timer on an STM32F10x
I'm trying to understand how to correctly setup the timer on an STM32F10x.
The board is running with an external crystal of 16 MHz, and I'm using the PLL:
/* PLLCLK = 16MHz / 2 * 9 = 72 MHz */
RCC_PLLConfig(RCC_PLLSource_HSE_Div2, RCC_PLLMul_9);
so the board ... |
H: What's the usage of two NPN transistors with their bases and collectors tied together?
I'm thinking to know what is the usage of these parts of this circuit.
Source
It's the schematic of UT70C Digital multimeter.
AI: The way they are connected they'll act as a bipolar 8~9V "zener". They would be for over-voltage p... |
H: What do I need to put my code onto a microcontroller?
I learned about coding a controller, but never actually put the code on the physical device. I am trying to figure out what I need to order to start developing a basic embedded system.
For example, if I have a PIC18F1330, I have MPLAB IDE and XC8 compiler. Great... |
H: VHDL delayed assignment problem
I want output to equal "11111111" on the first rising edge of the clock but it only happens on the second rising edge when I test the code with ModelSim. The code might look weird as a simplification of a more complex design where I have the same kind of problem.
code:
library iee... |
H: Replacing wires with threads?
Is it a good idea to replace wires that get bent a lot (e.g., around a hinge) with conductive threads? It's a 5V device using up to 1A.
Thanks
AI: Conductive thread is simply thread with wire woven through it, so it won't necessarily be any more robust.
The critical thing for reducing ... |
H: Explantation for fried charger with Multimeter
I have a 9v AC to DC wall adapter that I use to power my Arduino boards. The label says it gives 9v at 1000ma but I wanted to test the validity of the label to troubleshoot.
When I connected my probes to the terminals however it said 0 amps and then the green power li... |
H: Driving highly inductive loads destroys mosfet driver
Background
I am attempting to generate some relatively high voltages (>200KV) using a system of ignition coils. This question deals with a single stage of this system which we are attempting to make generate somewhere around 40-50KV.
Originally the function gene... |
H: Checking when a car horn is pressed?
I want to detect when a car horn is pressed. The only way I can detect it currently is using the voltage on its line.
When the car is turned on, there is always 12V being supplied to the horn through the battery i.e. When the horn is NOT being used the voltage to it is 12V.
When... |
H: About the leakage reactance of transformer
As known the transformer's equivalent circuit can be developed as below:
Assume the \$V_{1}\$ is the voltage applied to primary side, and \$V_{2}\$ is the voltage developed at the secondary load.
Now, let the primary side open circuit, and apply a voltage to the secondary... |
H: Transformer Efficiency Issue
Trying to improve on the transformer efficiency, I changed the configuration of the rectifier from half wave to full-wave. Below shows the configurations I used
Transformer turn ratio is enough so that the input side on the LDO is maintained well above drop-voltage + output voltage. Th... |
H: Build PIC development board on bread board
I have PIC24FJ128GA202 IC only. Since development boards cost too much, I would like to build a development board on a bread board and try some sample programs on it.
Like the image below:
Is it possible to build it this way?
Thanks
AI: It is possible if your PIC part i... |
H: If op-amp offset trims are provided, but not needed, what is the best practise for connecting them?
I'm using op-amps with offset trims available, but not needed as they already have very low offset voltage. What is the best practise for the PCB pad connections - should they simply be left floating?
(I'm beginning ... |
H: 24 VAC source unable to drive servo motor
Here's my power supply (schematic except without the transformer since my source is already at 24 V AC and using a 100 uF electrolytic as my smoothing capacitor):
24 VAC rectifier -> 100 uF smoothing cap -> LM317 linear regulator (typical application on page 10 of LM317, ru... |
H: VHDL: value isn't assigned immediately
I asked a similar question here. I thought that that answer would be applicable to this code but I have the same problem. I have a ROM that runs at twice the speed of my CPU (left out all the commands except 'OUT' to make it easier to understand). The reason it runs at twice ... |
H: Altium de-highlighting nets after using 'Find Similar Objects...' command
I can't work out why Altium is doing this, or how to undo it, or how to make it stop doing it.
It happens when I use the 'Find Similar Objects... ' option; all of objects that it hasn't found are faded out and I can no longer select them.
Any... |
H: Is this diagram correct?
I have created the below mentioned circuit diagram:
I just wanted to know that have I drawn a good/correct diagram or should I make any changes to this diagram? I have not added the resistors in diagram to make this diagram look simple.
Here is the use of this circuit: Rotating a motor acc... |
H: Breaking a 16-bit long int to write into eeprom?
I am writing data to eeprom AT24C16 using PIC microcontroller pic18f4520. Every address of this eeprom can hold 8-bits while I am using long int's to store data that are 16-bit in size. How to break long int into 2 8-bit parts to write them and how to get them back t... |
H: Charging cellphone from dynamo - safety risks
I want to make a dynamo charger to charge multiple smartphones at once. I have figured out the schematics, but before I put a smartphone in it I want to be sure it will not destroy it.
Schematics:
simulate this circuit – Schematic created using CircuitLab
So my biggest... |
H: Do AC voltages on datasheets refer to peak voltage or Vrms?
I'm attempting to find a relay to switch UK mains voltage (230Vrms); this gives a peak range of approximately 325V, -325V.
Consider something such as the datasheet for this relay. It has a rated voltage of 250VAC and a max switching voltage of 277VAC, are ... |
H: Why is it so hard to find component footprints?
When designing PCB's, I find myself very often having to make footprints for a significant portion of the components on my board. This tends to be very time-consuming, as (in Altium at least), dimensioning out land patterns for strange connectors or chips (those that ... |
H: What are the recommended trace width and clearance on homemade PCB's?
I know that there are multiple processes and lots of variables regarding homemade PCB manufacturing. Using the right tools it is possible to achieve professional levels.
I'm concerned for students their make themselves their first board. What cou... |
H: About induced current
This is a homework question that I have stuck for a while and couldn't able to come up with the correct answer.
So here is the question,
My thoughts towards this question
When I move the rod PQ with a constant velocity ,the area of
triangle RPQ inside the magnetic field increases .
Once the... |
H: make a device for USB ejection
I want to make a device for USB which is connected through usb to PC and offers an usb port.
The device should have a button which ejects (in Windows) the device plugged at the port of the device.
After some research...
First I wanted to solve this problem through a C# program- but I... |
H: Why do characteristic impedances matter only when traces are longer than half a wavelength?
Why are characteristic impedances of traces not considered when the traces are shorter than half a wavelength? I've had the same issue with light diffraction, which happens when pinholes are smaller than half a wavelength - ... |
H: Mounting battery terminal contacts in an aluminium case
I'm trying to mount AA terminal contacts in an anodised aluminium case. Given that the aluminium is anodised, does that mean it's not conductive and the contacts could directly make contact with it? If not, what's a good way to mount contacts on an anodised al... |
H: Bizarre Behavior in a Phototransducer Amplifier
THE GOAL:
I'm trying to measure light levels with a Hamamatsu S6428-01 photodiode (Blue).
THE CIRCUIT:
Below is the circuit that I have: an Arduino Uno, powered by USB, which is itself powering a ADA 4528-2 op amp. I have marked points p q and r for future reference:... |
H: how to convert digital signal(PWM) into analog signal
analog signal can b easily made by using PWM in micrcontroller but it is not a real analog signal. please tell me how can i convert PWM into real analog signal
AI: Did you actually attempt to search, at all?:
On StackExchange (possibly the most complete answer ... |
H: DATA_ALIGN Pragma - Tiva
What is the purpose of a pragma Data_Align in TI emb. compiler.
The datasheet explanation:
http://www.ti.com/lit/ug/spnu151j/spnu151j.pdf
"The DATA_ALIGN pragma aligns the symbol in C, or the next symbol declared in C++, to an alignment
boundary. The alignment boundary is the maximum of the... |
H: Can I use a line multiplexer as a level shifter as well?
I have 40 x 5V inputs that I want to read using 3V GPIO pins on the beaglebone black. I am planning on using 5 multiplexers (such as the 74HC151 or 74HC251) that will be sharing the 3 select lines.
I'm not sure what the best strategy for level shifting would ... |
H: What are "slash sheets", and how do they relate to PCB substrates?
I am trying to specify the stackup for a PCB. Previously I have used whatever the board house considered to be their "standard" stackup. This time I am looking at using FR-408 (pdf) because of its (relatively) low cost and (relatively) favorable h... |
H: How to solder micro stepper motor pins?
I have a hobby project where I would like to use micro stepper motors as shown in the picture below. However, as you might be able to see, the spacing between the pins is incredibly tiny and each pin is much narrower than the 24 AWG wire I was planning on using. In addition... |
H: What constitutes a Via-in-Pad?
Would any of the via's in the picture be considered a via-in-pad?
or is it only if it's dead center of the pad?
AI: I would think about it this way, why would you care if a via was "via in pad"? Because you want to treat it a special way, and perhaps because that treatment will cost ... |
H: True GPS Location - At the Antenna or Receiver Chip?
Suppose I have a GPS unit attached to an antenna through a 50 meter coax cable.
How would the location as calculated by the GPS unit be affected by the cable length? As a bonus question, how would the time accuracy of the GPS be affected by the cable?
AI: The ... |
H: About "leakage inductance"
I'm a little confused about the transformer "leakage inductance" for days. Per this text book, it gives a schematic view of fluxes flow in the transformer:
It's apparent that the two leakage flux will create separate inductance on each side. And it give s equivalent circuit:
You see, th... |
H: How to make Current to Voltage converter
I am working on level sensor which give output of 4-20 mA. I have to feed output of level sensor to an ADC of a micro-controller, to do so I have to convert it from current to voltage.Voltage range needed is 0-1.8 Volts.
So I have gone through some circuits below:
I want t... |
H: What do we need the op amp for in this current-to-voltage converter?
I'm still very new to electrical engineering and at the moment trying to get my head around the concept of the ideal op amp.
In Fundamentals of Electric Circuits by Alexander and Sadiku the following diagram is given as a "current-to-voltage conve... |
H: Why is there such a huge price range for BNC terminators?
I wanted to buy some standard BNC 50 Ohm terminators and was surprised when I saw multiple offers with prices well above 20€ per piece. I found others for around 2€ (same online shop) and now I am intrigued on why the expensive ones are more expensive. Are t... |
H: How is NAND Flash memory array organized?
Could you please explain how memory array organization calculated? Here I have attached snapshot of 2Gb NAND flash memory array organization. I can't understand the calculation of 1 Plane (marked in yellow color), but I do understand the calculation of 1 block.
AI: The imag... |
H: how long charge li- ion battery
I have \$3.7V\$ Li-ion battery \$3800mAh\$ and Solar panel \$U=5.5V, I_{max}=290mA\$. Battery will supply arduino with sensors taking \$100mA\$ current. How long will it take to charge the battery from the solar panel?
AI: It will depend on how you're charging the battery (i.e. how y... |
H: What's the requirement to DIY PD aware USB connector?
According to some research, I should be able to pull +12v from a USB power source assuming my device is some how telling the power source that it is ready to receive +12v?
I've seen a YouTube clip (can't find it conveniently enough tho) of a kid putting a resist... |
H: Choice of bypass capacitors for PIC18F4455
Does anyone know how many and what values of bypass capacitors I need for a PIC18F4455? The datasheet does not provide any information on this and I don't want to use more than what I strictly need, given that I don't have much real state available on my PCB.
Also, if anyo... |
H: Shunt capacitor as discontinuity in transmission line
As in the following circuit
simulate this circuit – Schematic created using CircuitLab
suppose that an infinite transmission line (with characteristic impedance \$ Z_0 \$) ends upon a capacitor \$ C \$, then another infinite transmission line (with the same cha... |
H: MSP430FR4133 is missing PxSEL1 register?
Hi there fellow MSP430 programmers! I'm new at this so maybe you can help.
I'm running into trouble configuring the MSP430FR4133 PxSEL registers. In the MSP430FR4xx Family User's Guide, it is stated that the pin function select is controlled by TWO 8-bit registers, PxSEL0... |
H: Can a voltage source be DC and generate a sawtooth signal?
Pretty much what the title says. I'm fairly confused with this simple question. Shouldn't waveforms which change amplitude be AC?
EDIT: So this is about a RAMP Type DVM (Digital Voltmeter). Can the input signal be both DC and sawtooth is my question?
AI: Ju... |
H: Software vs Hardware control
I was reading the Tivaware datasheet on GPIO:
http://www.ti.com/lit/ug/spmu298a/spmu298a.pdf
When I came across this(page 257):
"where GPIO_DIR_MODE_IN specifies that the pin is programmed as a software controlled
input, GPIO_DIR_MODE_OUT specifies that the pin is programmed as a softw... |
H: how to determine if system is matched in system
I'm concerned about matching. If you look at the pictures, there is a certain tracewidth optimized for 50 ohm that is then changed to fit the pad of the rf component. How would I measure the amount of reflection in an already built system?
Situations: The RF board is... |
H: RX/TX labeling standard
I'm familiar with the idea that RX means receive, and TX means transmit. Therefore, if I'm wiring two IC's together, feeding the TX of the sending chip into the RX of the receiving chip makes sense. How does this labeling standard extend to other devices that aren't either the source or term... |
H: How to design a metal plate for PCB
I am designing a Esp8266-based WiFi module and I'm not sure if I need one of those metal plates. They are suppose to protect a sensitive area from EMI/RFI, right? Also, how can I design one with custom measures and writing?
Here is an example:
This is with the shield on
This is ... |
H: Numbering format in code syntax
For the code, which I am referring following is syntax:
Write_Parameter(0x00);
In above line, what does "x" stands for and what is data size for x? My assumption is its dec format.
So, What other format, we can use?
Thank you.
AI: 0x followed by a series of digits means a hexadecim... |
H: capacitive touch screen
I am currently trying to build a capacitive touch screen. My end goal is to create a giant track pad/keyboard for my computer. Since abnormally large touch screens are quite pricy I have set out to build my own. Unfortunately it seems as though this has not been done before by regular ele... |
H: Integral and Derivative terms in PID control
Integral Term
My understanding of the integral term is: Sum of all errors since we started counting.
So, even though we have reached our desired final target position, the integral of the errors should be high (no?) since we started adding all the errors from when we we... |
H: Portable 1A battery phone charger
I want to make a little battery-powered portable phone charger with 2x AAs that outputs 1A.
I have seen similar USB powered battery chargers such as the Mintyboost but it only outputs 500mA.
For 1A output, would the design be fairly similar? Does anyone know what changes would be n... |
H: MOSFET Switching without gate voltage / LED Strip
I have ordered logic-level MOSFETS of the type IRLZ34N (for the sake of working on a Raspberry Pi) but I have problems in Wiring it up.
I have so far connected:
+12 to the +12v lane of the switch
FET Drain to the blue color of the switch
FET Source to the negative... |
H: 4-20mA Loop powered DAC
I was selecting a DAC for HART network and in the process I came across two terminology.
12-/16-Bit, Serial Input, 4 mA to 20 mA, Current Source DAC AD5420 and
16-Bit, Serial Input,Loop-Powered, 4 mA to 20 mA DAC AD5421
As per my understanding, the difference between the two terminology is... |
H: Simplest AC-DC: charging capacitor at needed AC input voltage
To implement a simple AC mains input circuit to charge a capacitor with low voltage DC I think that it should be possible to connect the output capacitor to the AC line through a diode, and a transistor which will disconnect the capacitor from AC line af... |
H: Is this transistor datasheet correct?
I was about to post a question asking for a schematic critique, although while checking things I've noticed a few things on the transistor datasheet that strike me as being a little strange. The datasheet in question is for an NPN, TO-92. The second page states the electrical c... |
H: Is it normal for a transistor running a motor to be very hot?
I've researched for a few hours but I'm still concerned.
I'm building a very low budget quadcopter (think toothpicks) and as I've seen on this site, a D10N05 mosfet would do the job. I've visited 3 of the largest electronics shops in my area but unfortun... |
H: Measuring currents between 100pA to 100uA
I want to measure absortion/resorbtion currents of dielectric when applying 1000V, 1500V, 2000V.
I have made a small currents measuring device using a LOG114:
I use : LOG114 with 1uA reference current on input I1.
The power supply for the LOG114 is made using an 78L05SM... |
H: Powering a Futaba S3003 servo
I'm working on a project and I need to use a Futaba S3003 servo, I'm about to buy a transformer that gives 6v, the thing I'm not sure about is the amperage.
Is this transformer ok? I can choose 3V, 4.5V, 6V, 7.5V, 9V and 12V, but its 800mA and I don't know if it is OK with the servo.
E... |
H: Series inductor as discontinuity in transmission line
Dual to this question is the following circuit:
simulate this circuit – Schematic created using CircuitLab
An infinite transmission line (with characteristic impedance \$ Z_0 \$) ends upon a series inductor \$ L \$, then another infinite transmission line (with... |
H: Understanding alternating current (sine wave)
I want to study the basics of propagating a periodic signal, i.e. sine waveform, which is a power signal.
Let us consider an alternating current and write its expression as
$$I(t) = I_m \sin(2\pi f t)$$
Let f=50Hz
In physics we have learned that there are mainly two t... |
H: How to figure out how much time you have for writing to flash when voltage source breaks down?
I try to figure out how I can make sure, that my controller (STM32F030K6) is always able to save a 16 bit integer to the flash when the power is breaking down rapidly.
This controller has an Analog Watchdog that fires an ... |
H: Show charge state of a car battery
I'm building a mobility music box, powered by a car battery (12v, 74Ah). What can I build into this box to show the current charge state (read somehow from a display if the battery should be changed)?
Will a simple voltage or ampere meter be enough?
AI: A car battery has some very... |
H: How to work with the MCP1702?
I'm reading the MCP1702 datasheet and there's the typical circuit on page 2 depicting a 9V source and a 3.3V 50mA output.
My question is: How come the current output is 50mA when the spec says that when Vr < 2.5V, Vin > 3.45V the min. output current is 200mA? How is the output current ... |
H: PCB Stackup - Current return path
It is a well known fact that high speed signal would have return current path on the plane right beneath it's PCB trace.
Suppose we have 4 layer stackup, SIG-GND-PWR-SIG with dielectrics CORE-PREPREG-CORE respectively. Difference between core and prepreg is that core has cooper fil... |
H: photodiode amplifier
I am a mechanical engineering student and I am working on a research project where we want to use a reverse biased segmented photodiode (OSI SPOT2DMI series) to detect deflections from a high speed laser. We are trying to detect very small variations in the laser signal so there is a large nois... |
H: confusing current readings
I know that Ohm's Law is V = IR but I am getting some very confusing current readings from multiple multimeters. Here is my very basic breadboard configuration:
V = 6v
R = 200 Ohms
I = Should equal 30 mA but it does not (see multimeter pic)
The multimeter shows 18.8 mA but I do not ... |
H: Making a simple solar-powered lighting system, a few concerns
I'm building a fairly simple solar-powered lighting system to use at home, which charges up a battery by day and then the battery powers a few bulbs at night, switching automatically. So far, I got that switching mechanism working with an LDR and a relay... |
H: Why does I2C look like this?
I'm trying to debug an I2C device, and the wave is looking really weird. Why is it curved?
AI: The ICs internally use open drain/collector drivers to actively pull the signal low so you see "fast" fall times. In contrast, when the drivers are off the line is pulled high through a pull... |
H: Precautions for powering up an old oscilloscope?
I have a Phillips PM3264 100MHz 4 channel analogue oscilloscope, I have not powered it up in around 8 years.
I have not been able to find a users manual, nor service manual as of yet, only a few pages of specifications from a brochure [pdf].
I am concerned that due t... |
H: How to restrain this soft latching power switch from eating too much current?
I am designing a two buttons soft latching power switch for a project involving a raspberry pi, li-ion cells I salvaged from the battery of a broken laptop, and a power booster from adafruit.
I wanted the circuit to be controlled by two m... |
H: How to program modules on assembled PCBs?
Suppose a Bluetooth module like the HC-05 is part of the PCB design. During production, how/when are the modules programmed? Is each programmed before or after assembly? If it happens after assembly, how are the pins accessed?
Thanks
AI: They either have programming points,... |
H: Splitting a big Power Trace to several smaller
I would ask if i can layout a big trace and split it into many smaller ones (see attachement)
I need to run a trace capable of handling ~5A. But the trace would be too thick to fit between the pins (screw terminals). My idea was to run a big trace and then use smaller... |
H: OP AMP fabrication technologies impacts on design
I am referring OP AMP selection guide for implementing it in medical application where it involves optical sensing using photo diode then I/V converter and ADC for data conversion.
My question is how OP AMP fabrication technology like BJT, FET, CMOS makes impact on ... |
H: Passive POE: Need 5V @ 2A at the destination
Having a bit of trouble finding the right information on google, and I'm worried I might fry some cables so I thought it best to ask some far more knowledgable than myself.
I want to connect 2 or more devices, giving them 5V/2A plus networking between them.
I figured to ... |
H: Reverse current protection on power-switching MOS
It was suggested in "Select power supply voltage using MOSFETs" that a second MOSFET can be added in series to prevent reverse current flow.
My question is, can I just reverse Drain and Source on the switching MOSFETs and not need extra MOS or diode?
.
AI: If you j... |
H: A/D conversion loop infinitly
I'm quit new one PIC microcontroller, and i'm stuck with a new problem.
I was using the A/D converter of my PIC18F46j50 to catch 4 push buttons on 1 PIN (RB2), and it worked well. But since I soldered a 32.768kHz oscillator for Timer1, it doesn't work anymore.
unsigned int HAL_SWITCH_G... |
H: High-voltage frequency divider
How can a frequency divider for high voltages be implemented? Is it possible to make it cheap and compact?
An application would be to mount it between the output of fluorescent lamp ballasts (delivering 20kHz at a high voltage above 500 volts) and the input of the lamp and change that... |
H: Relay or Transistor for DC Resistive Load?
I'm building a circuit that includes a resistive load that I have to switch, which is going to be supplied with ~200 VDC and 0.1 Amps.
I've looked at different mechanical relays, and typically they are specified as "30A@240VAC or 30A@30VDC.".
Ideally, I would like to use ... |
H: Is it possible to multiplex SIM cards using a CPLD?
I am building a hobby project using a GSM module and would like to be able to switch between multiple SIM cards, in case one stops working or I have poor reception on one provider (the project will be quite inaccessible once deployed).
Would there be any issues do... |
H: Old Radio RF Transformmers
I want to make a TV transmitter (http://electronics-diy.com/electronic_schematic.php?id=851). There is an RF transformer on it (T1:4.5MHz 1F-can-style RF transformer) that I want to find it from old radio circuits. There are a lot of transforms with different colors and different numbers ... |
H: Enhancement type nmos threshold voltage
in an enhancement type nmos when a channel is created then a depletion layer should be created under the n-channel which means electrons get a potential barrier to overcome.now is this potential barrier is included in threshold voltage??
AI: Your Channel is Itself in depletio... |
H: In current mobile phones, what are some specific techniques that prevent handling noise (rubbing, jostling) from being picked up by the microphone?
I've noticed that when using my smartphone the vibrations from my actions aren't picked up, or are picked up very faintly by the microphone. I've worked quite a bit wit... |
H: LM386 noise when using 5v power supply
I'm using LM386 with my guitar and currently I power it with 9v battery but now I want to switch to 5v power supply because I don't want to use a battery.
I want to use a 5v usb wall charger + sparkfun usb mini-b breakout but it doesn't work, it haves a lot of noise/static.
If... |
H: Finding gain from a transistor datasheet
I'm trying to work out the gain of a transistor, the datasheet is here, although I have extracted the relevant images here:
The datasheet gives the gain for Ic=5mA and Vce=2V as 25, and the remainder of the results seem to indicate something of a bell-curve of the gain plot... |
H: Is it OK to use the USB 5v pin as power source?
I am doing some stuff in my case and I need a power source for one LED from inside my case.
I looked up and there are two +5v pins on a USB header inside my case. Is it OK to use them as power source? Can it handle sustained usage?
AI: Usage that is within the USB spe... |
H: Calculate jitter of oscillator from PPM
I found oscillators with from 10ppm up to 50ppm and more, but how I can calulate maximum jitter of this oscillators?
With an online calculator I've found with 40Mhz and 50ppm this value:
2.500e-12s Max - Min Period (sec), so 0.0025ns
Can I assume that this is Max. Jitter time... |
H: Purpose of breadboard "studs" on base off micro breadboards?
I recently bought some micro breadboards on Ebay. Extremely useful little things. However each have two awkward studs on their bases. See the attached photo. What I'm curious about is their purpose? What might these "plugin" to or be used for? I th... |
H: Is it voltage or power of the signal amplified when the opamp amplification is given in dB unit?
Today, one of my colleague said that he entered a preliminary examination in a company after his job application. One of the questions is exactly "Design a non-inverting amplifier with 20dB gain.". The goal of the quest... |
H: RF: Do I need a resistor at line driver output for impedance matching?
I have a digital RF signal (~50Mbps max) passing through SN74BCT25240, a 25-ohm octal buffer/driver. This is on a 4-layer PCB with a ground/power planes and proper bypassing, etc. I was wondering do I need 50-ohm termination on the output of the... |
H: How Much Current Draw From Speakers/Amplifier?
So I plan on using the VS1053 Codec connected to a class D Amp (2 x 2.8W channel) with two 3W 4 Ohm speakers. If I supply 5V to this setup, what would the current draw be at full use?
Codec: https://www.adafruit.com/products/1381
Amp: https://www.adafruit.com/products... |
H: Wireless data exchange up to 2 bytes/s
I would like to set up communication between two Arduinos with a distance of 20 cm, but not more than 40 cm. I looked for an RFID solution, and I found a lot of PCBs which can be used to read and write to the RFID chip.
However I am wondering if it is possible to use such a PC... |
H: Is a buck regulator the best option for my needs?
I'm looking at using an MC33063 buck/boost inverter in a QFN package to step down 5-30V to 4.2V. This will be used to power an MCU, some modules, LEDs cosuming about 200mA max, optionally to charge a small LiPo, so the 1.5A is more than enough.
What I would like to ... |
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