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H: What is the difference between different types of GND
I would like to know the difference between different types of Grounds like AGND, SGND, Battery Gnd, PGND. Are all the grounds not same? Cant we connect the device to any one of these grounds?
AI: Though they all all contain "GND" they are not really mean the ea... |
H: Questions on Operational Amplifiers
What I've learned so far from Navy school is that operational amplifiers are used as a substitute for transistor amplifiers and they contain three main circuits: the differential amplifier, common collector amplifier and the push-pull amplifier. They are represented by a triangle... |
H: STM VCP USB_BUSY?
I am using STM32 VCP firmware, and I am sending data to my PC application
If i did not open my serial port in PC, and my firmware keep on sending the data it will cause USB_BUSY to happen, (i think the firmware transmission buffer is full and it is waiting for the PC side to receive data)
when I o... |
H: Shall I connect inverter with boat GND?
A friend of mine is building a boat. On this boat, he has 12V batteries with a 230V/13A transformer.
Recently somebody suggested he should connect the null with the ground. With DC, this is common practice. But how would somebody suggest doing the same with AC?! Polarity swit... |
H: Why feedback is needed in PLL FM Demodulator?
I am trying to build FM Demodulator in FPGA. The architecture I am trying to use is PLL-based FM Demodulator like the one below. I searched for the working principle of this demodulator but there is one thing I couldn't understand and I couldn't find an answer to. Why d... |
H: What frequencies do capacitors filter?
I've been trying to find out what frequencies get filtered out by which type and capacity capacitors, but cannot find simple rules that say "type X, cap Y filters xxx (k/M)Hz - yyy (k/M)Hz". Yet everything I read seems to indicate this is common knowledge - or does everyone ju... |
H: How does adding two Resistors in Series contribute to the sum of its resistances
I would like to know why by adding two resistors in series we would get a sum of it's resistances.I know by Ohm's Law that since $$R=\frac {V}{I}$$ it's certain that you would attain the equation $$R_t=R_1+R_2$$
But I would like to hav... |
H: Can I split a PCB using Altium?
I'm starting my first PCB using Altium and I want to take advantage of small dimensions PCBs cost in order to make my PCB cheaper. As an example take the image below. On the left there's the full PCB and, on the right, I'm splitting it just to make it cheaper (that's not my design, j... |
H: Why resistance should be increased for Photoresistor in night for Street Lamps?
I can't get why the resistance for a Photoresistor should be increased at night time as said in Photoresistors.
The reason is that I think that to turn on a light it's better not to have a higher resistance so that the electrons can con... |
H: Equivalent Resistance?
How do you find the equivalent resistance here? (I realized it's a Wheatstone bridge, but it's unbalanced, so that doesn't help.) I tried using Kirchhoff's laws, but there is no cell given.
AI: It looks like irreducible network - network which does not contain series or parallel connections ... |
H: Confusion: Power Bank and Mobile Charging
MI Power Bank 10400 mAh rated power bank. It has 93% conversion rate. It uses the USB standard to charge phones, so I am assuming a 5V output voltage. So the total energy 'content' = \$10.4A \times 5V = 52\$ Wh. Energy that can be converted = \$52 \times 0.93 = 48.\$
Now an... |
H: How do I get multiple voltage lines from a single PSU output?
Suppose I have a regulated power supply that has +20V and -20V outputs, and an amplifier circuit that uses them. I also have a push-button (not momentary) power switch with an integrated LED which requires 12V to run. What is a simple way for me to adapt... |
H: Optical heart rate sensor vs bioimpedance sensor?
I didn't know a better place to ask this, so here it goes. For activity trackers, Fitbit has the Charge HR with an optical heart rate monitor, while Jawbone has the UP3 with a bioimpedance sensor for heart rate.
Can you please explain the differences between the tw... |
H: Does an electrocardiography recorder put current/voltage on its electrodes?
(I do hope my question is not off-topic)
Currently learning about ECG recorders (Our 7-months old daughter has to have one during her sleep), I wonder whether this is a pure "passive" measuring device (like a multimeter) or not.
I do think ... |
H: How do I splice multiple (more than two) wires in-line?
When I look at many wiring diagrams, like this one:
(source),
I see wires which need to be connected to multiple points. This suggests that the wire will require multiple three-way splices in order to connect to all the right places. How is this done? I ... |
H: How do I create a Bode plot in Matlab?
I have calculated a transfer function for a specific system (a low pass filter):
$$H(j\omega)=\frac{1}{RCj\omega +1}$$
It seems to me that the standard way of plotting the frequency response of the filter is to use a Bode plot. Therefore I want to know how to do that in Matlab... |
H: Microcontroller soft off circuit not working - why?
I was making a board with an atmega328 mcu (to be used with Arduino libraries) to do some one wire communication stuff. Since I was etching the board anyway, I decided to try and implement a simple software off functionality, without putting much thought into it. ... |
H: How does a zener protect my microcontroller?
I'm connecting a 12V inductive limit switch for my 3d printer to a RAMPS controller (Arduino-based printer controller).
The RAMPS board operates at 5V, and connecting the 12V signal from the limit probe will surely fry the RAMPS board. A friend suggested the following c... |
H: Set RFID frequency
I hope someone can help me with a doubt about the way RFID works, regarding communication with RFID tags.
I am working with a Motorola FX7400 reader, I know it works in a frequency range (902-928 Mhz). I want to know if is possible to set it to work in a specific frequency while communicating wit... |
H: electronics voltage sensitivity
I have a 12v battery directly powering a handful of electronic devices (router, modem, hard drives).
These vary from 0.5a~2a so I have breakers on the (+) lines into the 12v dc power plug.
I'm noticing when I charge the battery through a 120v wall charger, the battery outputs up to ... |
H: Data Whitening Block Diagram
I would like to understand this block diagram and how it relates to the formula:
g(D) = D^7 + D^4 + 1
Supposedly this helps to generate a whitening word used within bluetooth radio, the empty boxes are shift registers. I just dont understand how that formula relates to the diagram. I do... |
H: What is data rate?
What is the definition of data rate?
What is the unit of it?
Is it related to successful bits?
AI: definition of data rate is the number of bits / characters / symbols sent over a specific time. The unit for data rate would be bit per second (b/s) or byte per second (B/s). Data rate is what the... |
H: Impedance Matching of Antenna and Amplifier
I've been doing a lot of research on impedance matching and I am just having a hard time understanding some of the specifics and I was wondering if someone here could help me out.
I have a 50 Ohm Antenna connected to an amplifying circuit which then outputs to a 50 Ohm sm... |
H: Pull up resistor on Schmitt trigger IC input?
I have two different circuits on two different boards. The output of board A, let's say, is optocoupler based and hence, it has a pull up on it. This signal is connected to board B through an interconnect board. In the board B, I have used a Schmitt trigger inverter gat... |
H: Connected 2-Pin Button switching randomly from LOW to HIGH
I got this ordinary 2-pin push button and now I'm trying to read its state.
Basically I want to turn a LED on and off.
My board is an Arduino Uno and the button is connected to GND and Digital Pin 2.
Also Pin 2 is configured as INPUT_PULLUP.
I followed the ... |
H: 230 and 240 transformer leads
So I have a transformer that is like 230 || 30 V.
One thing I don't get that on primary side it has the following leads:
0 --- 230V --- 240V
When it can be useful? I mean I can't think of situation when somebody would say "We should wire it to 240V, 230V will be a bad choice".
Isn't ... |
H: PIC18 how to explain : you write bit 1 by making TRIS input
I'm reading 1_wire header file for PIC18 with C18 compiler.
in the write_byte function, they specified that in order to write bit1; we make line input and that will take it high.
can we specify high or low output value in the TRIS port which specify i/o ... |
H: Ways to configure and persist settings in Arduino-based hardware
I'm currently building an Arduino-based LaserTag Game.
After solving a lot of technical challenges I'm now at the point of programming and configuring my first prototype.
Next challenges:
The "Taggers" should be customizable to the players needs (dam... |
H: Baudrate and BTR0/BTR1
I am creating an application that uses standard function that sets bitrate. The parameters required are BTR0 and BTR1. But the user of my application will enter the standard value of the Baudrate (eg. : Bitrate = 125000). How can i calculate BTR0 and BTR1 from the given value?
AI: The CanCase... |
H: Is it wrong to write HIGH to a pin used as an open collector?
I'm a software engineer playing with PICs and have an old PS/2 mouse that I am using (successfully), which has CLK and DATA connections as open collectors.
So I have configured the internal pullups on the relevant PIC pins and am setting TRIS to 1 to let... |
H: Replace a Solar Panel with a charging brick
I have a small solar lamp with a messed up solar panel. Now i want to replace the solar panel with a charging brick in order to charge my lamp. The question is what specification of charging brick should i go for so that i can charge my lamp. Below is a specification of t... |
H: Any reason I cannot just switch a transformer from a 555 to generate high voltages?
I had an idea to finally start using my nixie tubes and thought why not just switch a mosfet which switches a transformer to generate required high voltages for nixie tubes from a low voltage supply. When I googled all I found was t... |
H: What is the function of fuse here
The datasheet states that TPS2400 protects the load from an over-voltage, by disconnecting the load from the power supply (Q1 goes off), without blowing the fuse. Why is the fuse F2 here, if there will be no current flow at over-voltage or under-voltage condition?
AI: Fuse F2 prote... |
H: What is the test voltage of a ohmmeter?
Ohmmeters don't appear to make LEDs conduct which gives overestimates in the resistance measured (tested with a R1//(R2+LED) parallel circuit). So what is the voltage they apply to the circuit, assuming it is conventional? I assume it depends on the range selected (I seriousl... |
H: "Standard orientation" for stepper motors in data sheets
I just finished getting a SOYO 6V@0.8A unipolar stepper motor working, and wanted to know more about an issue I faced while doing so.
I used the stepping sequence below with an L293D chip to drive the current for the stepper motor:
So, I pulled up the datash... |
H: DC voltage stepping down but keeping current uchanged with no regulator
Is there any way to divide DC voltage or stepping it down but keeping the current peak unchanged? But I can't use a voltage regulator. In fact, I want to make a regulator 5V output into 4.5 ~ 4.7 V but keeping the current peak same. Current is ... |
H: Delay introduced by transistor
I have the following circuitry:
PWM-2V8 is a square 50% 40kHz signal as this (R37 not populated on this capture):
On P8, I get the following signal which is distorted and the duty is more like 65%:
Q1 = Q2 = 568-8001-1-ND
Q3 = 568-6084-1-ND
I have tried R37=0 and R38=1k but it's st... |
H: Help understanding the function of my circuit. (Bug swatter)
The important thing is the image below. I want to know how it works. Here's what I understand so far.
First I'll identify the pieces:
-The blue "packet" is a capacitor. Its a \$ 0.030 \mu F\$ with 400 V Capacitor.
-The resistance near to LED is a \$560... |
H: How do I calculate the cutoff frequency of a low pass rc circuit?
I want to calculate the cutoff frequency for a specific filter, but I can't find any formula for that.
I know the formula for the cutoff frequency of a low pass filter:
$$f_c=\frac{1}{2\pi RC}$$
But how is that derived in the first place? I don't ha... |
H: Temperature Sensor Verilog
Hello I have been working on an analog temperature sensor TMP36 and I am trying to get the temperature and display it on the NEXYS3 SSD. I am aware the NEXYS3 does not have an analog pin and I built an analog to digital converter using the TI ADC0804 an 8-bit ADC. The part I need help w... |
H: driving a 5v LCD with a 3.3v atmega328p microcontroller
Am using adafruit (American hobbyist electronics components retailer) breakout for the max31850 thermocouple amplifier who's data line isn't 5v tolerant. Therefore I want to power my atmega328P @ 12mhz 3.3v. I have been told this is the optimum speed for a 3.3... |
H: Why is the MISO not level shifted in this circuit?
I am looking at SparkFun's CC3000 breakout board schematic. CC3300 is TI's wireless module. The CC3000 operates on 3v3. And because the breakout board is intended to be used with an Arduino (which has a logic voltage of 5v), there is a 5v to 3v3 level shifter in th... |
H: The "AND" gate function
I am learning about the "AND" gate function in Navy school. What I know is that when a low voltage is at the base of Q1, the transistor is in cutoff mode since the collector is reading high (> 2 volts). This drives Q2 into saturation mode, meaning that its collector is reading a low close to... |
H: Derive the transition table for the following AB latch. Describe how it functions
I have no idea where to start or how to do this.......I have tried using the charactiresic equation of an SR latch, $$Q^+ = S +R'Q$$ and derive the equation for S and R from the drawing, with no success.....
AI: That circuit looks uns... |
H: Can program FPGA but not PROM on my Spartan-3A dev board
I decided to brush the dust off my Xilinx Spartan-3A starter board that I got a while back, and learn to use Verilog. So with the help of Pong Chu's book FPGA Prototyping By Verilog Examples: Xilinx Spartan-3 Version
I got a simple program written and compi... |
H: How to select gain for an amplifier before ADC?
The circuit has been simplified as shown in the picture. Signal source is connected with an analog amplifier, which amplifies the ac signal and also raise it by 1.5V to match with the range of the 0-3V ADC. Some characteristics of the circuit:
Signal of interest: 10k... |
H: Arduino - receive Ethernet W5100 signal to multiple arduinos
I'm after doing a device in which I'll use 4 AtMega328 chips; Since they'll all be mounted on the same PCB, and I need an ethernet connection for them, I was wondering if there's a way to share the ethernet signal from the WizNet W5100 shield to all 4 of ... |
H: Connecting three keytars to the NES
Let's suppose I have three keytars, such as this model. I want to hook them up to the NES (Nintendo Entertainment System) in some fashion. The NES has a controller port I can use that is wired like this. So, basically, a serial port with three input pins and one output pin. (Many... |
H: Using a motor with DC
I am using a Lego DC motor with a 9V battery which can provide up to 1A of current. I called Lego support and they said the motor draws 300mA of current. What does that mean? If I plug the motor to the battery will it use 300mA of current or will it use as much as my battery can provide and da... |
H: compensate for missing leds
I bought a small DIY infrared emitter today, but two of the LED's are missing.
The data sheet for the LED's is also missing.
The schematic is like this (a bit bigger):
Power source is 12V.
There are 3 LED in row followed by a 100Ω resistor.
Lets say L5 and L6 are missing. Is there a wa... |
H: Limiting small signals to one direction (ideally with passive components)
My setup is as following:
I use a Y-Cable for splitting an audio signal to two devices (boxes and earphones). The headphones have quite big speakers so they act also like a microphone - feeding back the signal to the boxes which then amplify ... |
H: ideal state of SPI MOSI and MISO pins?
Just wondering , If some how the MOSI and MISO tracks which connects the slave get cut. At that time, its disconnected from the slave.
So if the micro controller tries to read data from MISO pin, what will it read?
AI: It will read whatever the MCU is configured to read on tha... |
H: Transistor with different voltage in colector and base
I have a small LED of 5mm and an arduino powered by 9V. When I connect the LED to Vin (9V) using a 330 ohm resistor the LED brights very high. When I connect the LED to 5V (from arduino) using a 330 ohm resistor the LED brights very low.
Ok, that's supposed to ... |
H: Construct an AND gate from XOR gates
I was able to figure how to make a NOT gate easily enough, but I'm stumped trying to figure out how to make an AND gate. Is it even possible?
AI: No. Due to the both complementary and symmetric nature of XOR's inputs and outputs there is no way to configure any number of them to... |
H: How can I mount a DS18B20 tempreature sensor to a large heatsink?
I want to monitor the temperature of a large peltier element's heatsink to control a fan. I think I'm going to use a DS18B20.
The 3 pin TO-92 looks like it's plastic, so I'm already worried about low thermal conductivity.* However, how should I secur... |
H: why capacitance depends upon frequency physically irrespective of mathematical fact?
Sir,I know that when f=0 capacitive reactance will be infinity according to mathematical formula and thats why capacitor blocks dc.But what is its physical significance?I mean why capacitor blocks dc when frequency is null?I really... |
H: Breadboard header for usbasp
I am not able to find any breadboard headers for this particular usb asp connector
Here
They do exist because I've seen then at school, but I can't seem to find them online. I bought breakable male male pins, but they are too short to fit in the board. I also bought a black header for i... |
H: Instrumentation (or diff) Amp saturating when measuring low voltage
I need to measure (amplify) a very low voltage, by low I mean in the order of 20 uV. Right now, using a lab multimeter, I am clearly and repeatably measuring the voltages so I thought that amplifying it to about 1V in order to measure it with a 10b... |
H: What is the purpose of holes on edge of the PCB?
Here is a photo of one of Texas Instrument's RF EVMs.
Please pay attention to edge of the PCB that has multiple tiny holes. I marked 3 of them with a red circle on the photo.
What is the purpose/benefit of them? The edges are V cut, is it something to do with it? Or... |
H: Can I use a halogen transformer as a power supply?
I have an electronic transformer which is meant to be used to drive a 12v halogen light. The specification on the electronic transformer box says 220-240VAC input, 12VAC output 20-60W.
When a 50W halogen bulb is connected to this electronic transformer the voltag... |
H: Clock distribution gone wrong
I have had EMI problems in the past and I have decided to implement clock distribution with termination.
I have a 25 MHz crystal that travels through a 50 \$\Omega\$ strip in the PCB and splits into two. After the split the strips have an impedance of 100 \$\Omega\$. Each strip goes t... |
H: Taking the edge/ring off a clock signal with an RC circuit?
I'm designing a board for a hobby project where I am using a lattice machxo2 cpld as a system interconnect.
The cpld needs to be clocked at 80-100MHz, and because I sprung for a cheaper cpld, it has no on board PLLs. The easiest way for me to clock it is ... |
H: What Does Rated Load of a Tactile Switch Mean?
I want to connect a tactile switch to an GPIO pin of MSP430 (which runs on 3.3 volts). The datasheet of the micro-controller says that IO pins can withstand max current of 6mA.
The tactile switch I am interested in has rated load of 12V and 50mA.
What does it mean? Doe... |
H: IR2110 LTspice simulation weird behaviour
I am obtaining weird voltage behaviour at the gate of my high side mosfet controlled by IR2110 which is controlled by PWM.
PWM configuration:
Vinitial = 0
Von = 5v
Tdelay = 0
Trise = 7u
Tfall = 7u
Ton = 150u
Tperiod = 200u
For the simulation I use TRTOL = 7 and I am using... |
H: Controlling an electric motor through labview without knowing its speed
I'm having a little trouble running my final bachelor experiment. My group and I are to find out what exactly causes extreme high frictional forces when pulling a steel cable through wet sand by varying the height of the sand above the cable.
W... |
H: Using the PORTB interrupt on change feature with XC8
I'm making a program to learn to use portB interrupts on the PIC18F2520.
I made a program, but it's not working correctly. The program is all time lighting and turning off the led, and the led's state should be changed only with a change in some portB pin (I'm u... |
H: Why do I get 'Unmatched Nets' in Altium and how do I remove them?
I'm trying to import a Schematic to PCB in Altium and I get this message that there are unmatched nets cropping up:
The PCB is empty, I've searched in the Schematic for them but I can't find them. Do I match them or is there a way to delete them? I ... |
H: High Altitude Balloon Communication
Our team is planning to make a HAB (High Altitude Ballon) project for our university. We are planning to use XBee pro 868 RF modules (we are in Europe so we can not use 900 MHz band). We have to communicate to the base station from the payload from 20-30 km distance. My question ... |
H: Trouble with first part of Experiment 11 (Make: Electronics) when using multimeter
Here is my circuit. It works well, as described in a book, but I want to understand it better, so I want to check voltage on capacitor. But when I do it, LED doesn't blink and voltage goes up to 4V. When I turn off multimeter - it wo... |
H: Real time tasks with CooOs
i am using CooOs with 4 tasks.the problem is that only the first task run (indefinetly).What i want to do is to toggle each task 3 seconds then switch to the other.I know that i can do that with timers or systick but i need to handle CooOs.
#include "stm32f4xx.h"
#include "stm32f4xx_gpio.... |
H: RC Filter Circuit Question
Given the image below, we know that the second filter circuit is a Passive Low Pass Filter circuit. I'm assuming it is still a Passive Low Pass Filter with a different corner frequency. Am I correct? So my transfer function for the top circuit is just a voltage divider, which is-
$$\frac{... |
H: Driving a 4.5V motor with PWM from an Arduino
This is a basic question but I would appreciate help. I have:
An Arduino
A 4.5V DC motor
Various transistors, like BC337, 2N7000, 2N2222A
What I'm trying to do is very simple: control the motor with the Arduino. I want to control it with PWM, so I can change the spe... |
H: Power management at thermal power station
I have weird question, but I hope somebody can give at least hint what should I read to understand the concept.
Imagine situation:
There is thermal power station and a city that takes power from it. As I understand power station works 24/7 and providing electricity. Now w... |
H: What is the device used to diagnose bad eletronic hardware?
I'm quite new to electronics repair and was wondering what is the device that is used to diagnose electronic hardware such as chips and power voltages. I'm not talking about a multi meter, but the ones that look like a big box with the wavey lines on the s... |
H: Does an ATX power supply have any isolated outputs?
I am working on an application that requires isolated power inputs.
Wondering if the standard ATX PSU has any isolated outputs?
Why are we having multiple ground pins on the Connector?
AI: The outputs of the ATX power supply are isolated from the mains. The outp... |
H: RGB control with MOSFets
I would like to control RGB leds , or other PWN channels , using a micro controlelr, and MOSFets transistors- to push high current/voltage .
I know that MOSFets, are usually not linear-means a vgs above some voltage will open them, with an exponent curve .
My question is , if i set a PWM s... |
H: Arduino analog input higher than reference but lower than 5v
I'm going to use a very precise potentiometer that can measure angles from 0 to 3600 degrees (10 rounds), but I only need the first 180 degrees or so in this project and I need it to be more precise than 3600/1024=3,52 degrees.
I thought about connecting ... |
H: Lost in desert - charge the phone with car battery
First of all I'm not a student nor a engineer.
Pretend I'm lost in the desert with just a car with a broken engine.
The battery of my phone is over.
Is there any chance I can survive (charging the phone a little bit to call for help) or I am a dead man?
If so, how?... |
H: Do I need zero-crossing detection for controlling a heater?
I need to control a heater element (about 500W) using arduino. For switching part I would go with zero-crossing SSR or zero-crossing optoisolator and triac (the second seems to be cheaper).
The question is do I still need a zero-crossing detection for the ... |
H: Relay - Datasheet Max DC Voltage
This may seem like a dumb question, but I want to be sure. In the below datasheet, what is the DC voltage the relay can handle? I am assuming it is the Contact Capacity 24 VDC, 1 A.
Micro 1A SPDT Relay
(275-0240) Specifications Faxback Doc. # 45621
Contac... |
H: How to tristate output digital pin on a pic 16 series microcontroller?
I know that I can set digital output pins as high and low like this in c:
OUTPUT_PIN = 1;
OUTPUT_PIN = 0;
Is there any way to set that said pin as tristate or high impedance output, as some external chips (I'll be using sram chip) require trist... |
H: Unknown voltage in IR pulse sensor circuit
I've build a simple circuit based on the sketch from here: http://makezine.com/projects/ir-pulse-sensor/
simulate this circuit – Schematic created using CircuitLab
However, after connecting everything I have strange readings on output. It is all the time value around 60mV... |
H: Need help in understanding MUX-NOT flip-flop
I need help in doing practice problem:
A MUX-NOT flip-flop (MN flip-flop) behaves as follows. If M=1 the flip-flop complements the current state. If M=0, the next state of the flip-flop is equal to N. Derive the truth table and excitation table for an M-N flip-flop.
My b... |
H: What does delta stands for in ModelSIM?
I ran a simulation for a combinational logic circuit with 8 inputs, 4 outputs inside MODELSIM. When I view the simulated waveform everything looks fine, however when I export result to a list file there are some intermediate valued related to deltas inside a time slot like th... |
H: Why does this EPROM have comb-like structures around the wire bonding pads?
I took some pictures of a Microchip EPROM die from the late 80s / early 90s (I can't recall the exact part number). The wire bonding pads are surrounded by a comb-like structure. What is the purpose of this structure?
AI: They are probably ... |
H: Refrigerator Relay - Need replacement
I have a broken Kegerator and need some insight. I'm familiar with electronic circuitry, but far from an expert. Everything (temp display, internal fan, change set temp) appears to be working as it should, except the compressor never kicks in. I believe I narrowed down the issu... |
H: How to reduce 5 volts to 4 volts 1.5Amp with minimum components used?
I am trying to reduce 5 volts high current source to 4 volts with at least 1.5 amperes. I searched the internet, but I could not find 3 pin voltage regulator, 5V(in) 4V(out)voltage regulator.
I think voltage divider is an option, but it consumes... |
H: Is there more to a Microcontroller than a few logic gates?
I am a software developer (using high level languages like .NET,C,C++ etc) trying to understand how computers work at a lower level.
I asked this question a few days ago: Lower level system development. I have setup my arduino and I have written a few prog... |
H: What's the purpose of the ground plane?
What's the purpose of the ground plane?
I guess it's a pretty basic question and I tried to understand it by reading http://en.wikipedia.org/wiki/Ground_plane#Printed_circuit_boards but I still don't really get it.
The "allowing the designer to ground anything without having ... |
H: How much current can you pull safely off a standard AAA battery?
This might be a stupid question. But how much current can you safely draw from a AAA battery.
I am currently powering my project from a worktop power supply and it draws at 5V 0.45A during normal operations and peaks to 0.7A. Now I need to make it por... |
H: Best resistance for RED/BLUE 3 lead LED
I have a project where a PCB has been manufactured with an error, where a 3 lead BI color LED (red/blue) has a single resistor to limit the current for both colors. I can fix this by hacking apart the PCB but I would like to know what resistor value I could potentially use to... |
H: Same address for different registers in LPC2418 UART
I have a very basic question regarding LPC2418 UART. The UART has got different registers with the same addresses. So while loading the data from the test bench, will it not load into all the registers?
1) For example,RBR(receiver buffer register) and THR(transm... |
H: How do you calculate the current and voltage when the emitter is grounded for saturation mode
For example, assume you have this transistor with a grounded emitter:
Since we are dealing with a saturation mode, \$v_{ce} = 0.2 \$ making the drop across the resistor 9.8 v. The current going through the collector is \$... |
H: Driving an infrared LED from a coin cell
I am designing a remote-control type IR transmitter that will be powered by a coin cell battery (i.e. CR2032) and commanded by a microcontroller. The LED is pulsed at around 40kHz. How can I ensure that the LED current will be consistent as the battery discharges? Here ar... |
H: stack implementation in 8051
I have a doubt on stack implementation in 8051 and I don't even know if I'm asking it in right way so please pardon me. I've been reading stack implementation in 8051 and many textbooks and references it's mentioned that when we push the data then first SP is incremented and then the va... |
H: How to design and implement a sequence detector
I have to implement a Moore machine that has an input L and an output Z.
The input line L provides values of 1 and 0 as input, in a random order.
The output line Z takes the value 1 whenever two values of 0 and two values of 1 have been detected in the input, no matte... |
H: How does underdriving a powerful (eg. 50w, 100w) LED chip work?
My question concerns under driving an LED chip.
Unlike quality brand chips (Bridgelux, Cree), in my experience, under-driving non-brand ones make things more long lasting and favorable.
Using the potentiometer on my quality LED driver, I can lower or i... |
H: Is it bad to route a trace edge of a rectangular pad?
I got a quick friendly critic from someone in production for the below trace that I should not route the trace from the edge of a pad. What he said that it would create an extra force to the trace that might cause problem especially for smaller pad size in the p... |
H: AC Analysis Mindset
I'm just trying to solidify my foundational knowledge of ac analysis. So when approached with a basic circuit, lets say a RLC circuit, should my first instinct be to convert each group of components into a Z category. For example, when looking at active op-amp filters (miller integrator with inv... |
H: Need help for identifying components
I have bought a shocking gum which gives a small electric shock when you pull a side, like this one : http://img.weiku.com/waterpicture/2011/10/31/20/Shock_Chewing_Gum_634577515693532881_3.jpg
I wanted to know how it works so i opened it and there are two components i can't iden... |
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