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H: Arduino USB Protection
I am an absolute novice when it comes to electronics. I want to use a PC to control an Arduino UNO clone that will in turn control a
strip of 122 neopixels. My fear is that I will somehow damage the PC.
These are the WS2812B LED strip and Arduino UNO clone I plan to use:
https://www.amazon.co... |
H: How to select current sense resistors for ir2136 ITRIP signal
Looking at the datasheet of the IR2136 it suggests this little resistor network as input for the ITRIP pin.
https://www.infineon.com/dgdl/Infineon-IR213-DS-v01_00-EN.pdf?fileId=5546d462533600a4015355c8a02116a5
I understand the basic principle of current... |
H: Measuring input current of opamp
I want to measure the current that goes into a noninverting opamp input. I've setup my experiment as follows:
I can't measure the voltage drop across the 10M (R1) resistor directly since my DMM has an input impedance in the megaohm range. So, i have to measure the voltage on the ou... |
H: "31WOC" on a boost converter, but what datasheet goes with it?
Long shot, I know...
I have this Boost convert 1-5V in out 5.1-5.2V and I hope to modify it for a different output voltage.
So I'm trying to identify and find the datasheet for the main chip.
I think the chip reads 31WOC, but I can't find a datasheet... |
H: Preventing Verilog module from being optimised away
I have tried to put lots of inverters to stress test my Spartan 6 power supply as recommended here. Here is the basic module:
module inverter(
input wire clk
);
reg [7:0] inverted;
always @(posedge clk) begin
inverted <= ~inverted;
end
endmodule
I was... |
H: How does ESR affect cutoff frequency calculations for capacitors?
I'm interested in estimating the cutoff frequency of a capacitor in a simple RC circuit. Since the capacitor and resistor are in series, can I simply add the ESR value to the resistor value?
For example, if the ESR is 0.5Ω and my load is 1kΩ, then is... |
H: Draw Bode-Plot of a transfer function
I want to draw the bode plot of a tranfer function:
$$
H(j\omega)=\frac{100j\omega T}{j\omega T + 10}, T=1s
$$
Now I have
$$
H(j\omega)=\frac{100}{1 + \frac{10}{j\omega T}}, T=1s
$$
Using a double log scale:
$$
20*\log{H(j\omega)}=20*\log{\frac{100}{1 + \frac{10}{j\omega T}}}, ... |
H: Setting LMC6001 offset voltage
I have got two LMC6001 samples.
I will use them for pH sensor interfacing.
With one LMC6001, I can cope with high input impedance errors.
But I want to set offset voltage near by to 2 V.
Can I make offset circuit with other LMC6001?
AI: You don't need the second opamp. These are t... |
H: Recursion versus Tail Recursion on an Arduino
In computer science, recursion chews up a valuable and limited resource – the stack – and can lead to an unrecoverable type of runtime error: the dreaded StackOverflow. Tail Recursion however is a form of recursion that doesn’t use any stack space, and thus is a way to ... |
H: L200C voltage regulation
I have a battery that's designed to power a MacBook Pro (it's not an internal battery, it's an external battery meant to act in place of a charger, so it's got all the monitoring electronics internally).
Now, I wish to use this battery to power an iPhone dock. This dock has internal batteri... |
H: Low Cost FPGA for 500MHz FIR Filter
I need a 500MHz FIR filter for filtering ADC samples (500MSPS).
After the filtering a few samples needs to be stored in a buffer, for a simple peak detection algorithm.
I have been developing some VHDL code, and used a Xilinx FIR filter library to create the filter.
But after loo... |
H: Bluetooth simple oscilloscope
I was thinking to make a simple oscilloscope which can measure at least 2MHz signals, that would be enough, and it will be connected to a PC, or Android device.
First, I tought to use USB to connect the "oscilloscope" to the PC or Android USB Host capable device that would give me abou... |
H: Testing Oscillator Over Temperature
I want to characterize the frequency inaccuracy of several silicon oscillators over temperature to see which one will work best in my end application. If I populate the oscillator on a bare-board and solder a coaxial pig-tail to the trace/GND will that suffice? Since the oscill... |
H: Rewiring KVM Buttons
Background: I'm working on a project that would allow a number of people to hook up their laptops to a single monitor through a KVM and use buttons on the desk to control who has control of the monitor. Originally, the plan was to use buttons with microcontrollers to send keyboard shortcuts to ... |
H: Coils! Does the material used matter?
I've been making some coils with wires and I find out that sometimes they work and sometimes they don't work at all, the inside of those that don't work are some what more "silver-ish", more "metal-ish" like iron. While the coils that do work do look more thin like copper. Does... |
H: Choosing power supply, how to get the voltage and current ratings?
Power supplies are available in a wide range of voltage and current ratings. If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify? What if I don't know the device's specs, but... |
H: How to drive high powered LEDs as efficiently as possible
I have come across some very high powered LEDs.
Datasheet for LEDs:
http://www.cree.com/led-components-and-modules/products/xlamp/arrays-nondirectional/xlamp-cxa2011
For these high powered LEDs, how can I make a driver circuit that will be energy efficient, ... |
H: Transformer labeled 120v-60hz-35va-12v - What exactly does it do?
I have a pool light whose bulb physically broke, but I've found a way to open the water-tight bulb enclosure to get at the actual bulb. I'm trying to either hunt down a replacement bulb (rather than the whole expensive assembly) OR make some LED magi... |
H: How do I get started with uCLinux?
Right now I have ported an application from LPC2478 to Cortex M3 (LPC1788) and things are working fine at 120MHz.
I am thinking of porting uCLinux to my LPC1788 custom board.
The board consists of around 4 MB of NAND flash and around 32 MB of RAM. Is this enough?
Frankly, I do... |
H: What sensor to choose to track human presence indoors?
This is a hobby project about home automation. The idea is that of distributed system of cheap microcontrollers that take measurements, communicate, output data and control appliances.
One important task that this system should perform is detect at every room i... |
H: How to make 95%+ efficiency voltage regulator?
I need to make an 11 volt voltage regulator. I would really like this to be step-down, not a linear voltage regulator because I am going to be drawing between 1-2 amps at 11 volts, and if I was using a linear voltage regulator it would get very warm. The input voltag... |
H: How it will work if i solder thin wire with thick wire
I have a simple power supply for a rc airplane. I need to connect the speed controller to my brushless motor. The motor has very thin wires without a connector. But the speed controller has thick wires. I would like to connect them.
Will it heat the wires?
AI:... |
H: PWM speed controller with rectifier as voltage regulator?
I was looking around for a voltage regulator when I thought of this, so it might be completely crazy. And I'm sorry if it is.
BUT...
Could I use a PWM speed controller as a voltage regulator if I were to use a cap to "smooth" out the voltage, and a simple... |
H: SelectMap: Who drives the pins: FPGA or Microprocessor
I'm reading this application note regarding SelectMap image loading for my Spartan6. On page 2 I read:
The device has properly powered up, but the internal configuration
memory needs to be reset. This portion of the configuration flow is
signaled by PROGR... |
H: Electrical element instead of diode?
What electrical element can replace diodes other than transistors in an AC circuit ?
AI: There are many theoretical methods you could use to replace a diode. The complexity and cost would mean it is not really feasible on any sort of scale, but it is certainly doable.
Take for e... |
H: What might be the cause of high pitch sound coming from a switching regulator circuit?
We designed a switching regulator circuit using a 1.5MHz, internal-switch, switching regulator (semtech.com/images/datasheet/sc185.pdf). Vin is 5V, Vout is 3V3. We have an input capacitor (47uf), an output capacitor (47uf) and an... |
H: Using 4 digit 7 segment LED
I have a 7 segment display that has 4 digits. What will I need to make use of this? Can a single microcontroller handle the operation? I mean PIC16F690...I saw also a MAXIM chip that drives these kind of displays...is it absolutely required?
Here is a picture from the datasheet, I don't ... |
H: Smart charging circuit for NiMH battery pack
I want to build a solar powered charger for a niMh battery pack to run a microcontroller. What are the fundamentals of building a smart circuit that will not overcharge the battery and will also allow current to be pulled directly from the panel
AI: In most cases with a ... |
H: What is the size of a normal potentiometer screw hole?
I have a potentiometer that looks like this:
http://www.parts-express.com/images/item_standard/023-606_s.jpg Fig.1
I don't want to solder wire onto the leads. Instead, I want to do something like this:
Fig.2
What is the standard size of the hole that I need... |
H: how determine the RC time constant in PWM digital to analog low-pass filter?
I 'm looking for the best RC time constant and its reason in a PWM to convert digital signal to analog based on duty-cycle and frequency and other parameters. PWM frequency is 10 kHz.
AI: The best RC is infinite, then you have a perfectly ... |
H: How do the different kind of lamp dimmers work
Hooked up the scope to a dimmer expecting to see how it altered the waveform, and didn't see it do much of any difference from all the way down to all the way up.
I bought an LED bulb and was told it needs a "special" CL dimmer. How do the different kind of dimmers wo... |
H: Thicker solder harder to melt?
I'm trying to do some soldering on a PCB with a 20 watt iron and 1.2 mm 63/37 solder. From what I can understand, I'm supposed to touch the iron (has been tinned) to the point and heat it up then touch the solder to the point and it should start melting. But it takes like 20 seconds... |
H: Touchscreen : how to choose?
I am working on a small touchscreen extension to implement into a robot (show debug, command some basic functions, show points on a map where the robot has to go, etc...).
Microcontrollers used are Cortex M3.
I am pretty new to the world of touchscreens and I see there are different typ... |
H: Flip flop/latch with isolated differential input and differential output
I am looking to make something that takes a pulse of floating voltage (say from a feedback coil of on a transformer), and maintain a differential output voltage depending on the sign of the amplitude of the pulse. Then when another pulse comes... |
H: How long will it take to completely run out of power for two A23 batties(12volt each) on a serial circuit with 6 leds?
I'm connecting 6 LEDs serially with two 12volt batteries. Each LED needs 3.2 volt and takes 20mA of current.
I'm using two alkaline max 12 volt batteries(A23 LR23) and ATC is their manufacturer.
I ... |
H: SelectMap accepts FPGA image but does not enter the startup sequence
I am loading the image of my Spartan 6 and it seems that it cannot go to the final step of the process: the "Startup Sequence". After I load the image byte by byte, and add a lot of extra clock cycles at the end, the status register of the FPGA re... |
H: Logic Conversion 3.3V to 5V (Current Related) 74HC 74HCT
A beginner style question.
I'm attempting to perform some logic level conversions on 3.3V signals to 5V using the 74HC4050D powered at 3.3V and 74HC541 powered at 5V. Is it OK to directly connect the outputs of the 74HC4050 to the inputs of the 74HC541 ? or d... |
H: avr adc differential mode frequencies
I know that in single ended free running mode the following equation holds:
f_ADC = f_clk/N = 13f_s
where f_ADC is the ADC frequency, f_clk is the avr's clock frequency and f_s is the sampling rate.
The above equation means that if I want to convert an analog signal with a max ... |
H: Integrating another binary
I am building a binary for ARM using GCC and Crossworks. I have a secondary binary image that needs to be loaded to another IC during start up.
I like to integrate this binary to my tool-chain, in other words, I make this binary part of my image and every time I build this binary gets in... |
H: SelectMap: Should HSWAPEN be high?
I'm in the process of debugging microprocessor loading of a Spartan 6 image through SelectMap. The HSWAPEN pin has caught my eye. In my design it is pulled low via a 10K resistor. However, when reading the status register I notice that the HSWAPEN pin is read as high, and I've con... |
H: Finding air wires in Eagle
I am almost done routing a board. However, Eagle is telling me that there is still one more wire. I have looked but I just can't seem to find it. Is there a way to make Eagle tell me where it is?
AI: I can think of three options:
Zoom out as much as you can then use the route tool on... |
H: Inexpensive Frequency Counter and Display for clock generator
I have the desire to add a frequency display for a clock generator. Certainly not necessary, I can use my DNN, but it would be nice, I found a veritable plug & play frequency counter and LDC display for in excess of $50 USD at Digikey. I didn't have to p... |
H: How do they calculate the output power?
I'm building a quadcopter using Cortex A8 and I would like to use this USB WIFI dongle.
According to the description this is 3000 mW. What does this mean? 3000 mW consumption? In the USB 2.0 the maximum power can is the following 500 mA x 5V = 2500 mW. What is the 3000mW in t... |
H: Thevenin equivalent circuit with current and voltage source
I have the circuit below and I have to calculate complex current i1using thevenin equivalent circuit method:
I tried to follow the rules and open the terminal AB across the resistor:
I want to ask if this is a correct way to convert the circuit to theveni... |
H: What would cause a watch battery to leak?
I am using a CR1220 Lithium Manganese Dioxide battery to keep a real-time clock chip running during periods when batteries are removed from a device. The battery is only connected to two pins on the RTC that are designed as battery inputs.
The circuit works as expected for... |
H: NMOS FET selection for reverse polarity protection
I am working on a reverse polarity protection circuit, similar to that in Figure 2 of SLVA139: Reverse Current/Battery Protection Circuits. Here is my circuit:
My case is slightly more complex due to the possible input voltage ranging from 5-40V. Most MOSFETs seem... |
H: Safety precautions working with high voltages (Nixie Clock)
I'm building a nixie clock kit with these instructions. I'm up to the part where I have to test (page 17) the high voltage components (the power supply is 12V 250 mA) which is up to 170 volts (page 5) and is potentially lethal. Now I don't know if they p... |
H: Using a Shunt Resistor to measure current
Usually when we measure current, we have to break the circuit and place the ammeter in series.
However, if we want to make it easy to measure current at various points in a permanent circuit(for whatever reason), can we add very low resistances in the circuit at those poin... |
H: spotify controlled by arduino
I want to build a spotify controller [next song button for the moment] with Arduino
to build something like this song changer physical song changer
What do I need to control my spotify? using a windows machine? [using processing?]
the examples I have seen use a mac and AppleScript spot... |
H: Electrons Flow in cables
I'm Trying to understand how the current flows and how network cards receive the electrons (packets) in a Ring network (all the servers are connected to the same cable).
My question is in the case of a broadcast one server will produce current and put it on the wire and then the electrons ... |
H: Explaining a car voltage regulator circuit
I need to come up with a solution for a voltage regulator to be used in a vehicle, regulating ~12V from the car battery to 5V used by Atmel AVR microcontroller.
I've found this schematic on the Internet:
While I understand the most part of how this circuit works, I have a... |
H: What is a multiplexed network?
What is a multiplexed network?
Multiplexing means many to one and sending the result over the network. As far as I know, Control Area Network (CAN) supports multiplexing. How?
CAN is said to support multicast, one to many (kind of de-multiplexing).
Then what is multiplexing and a mult... |
H: Trying to get that tube sound from a gainclone amp
A Gainclone amplifier makes for a nice simple benchmark/monitor amp. It is a class AB linear amplifier capable of 20 W - 120 W of power, and is based on a monolithic amplifier chip such as the LM1875, LM3875, LM3886, or LM4780.
What different ways are there to add... |
H: On the use of "BLOCK INTERCLOCKDOMAIN PATHS"
I based an FPGA design on Lattice reference code that, in the timing constraints .lpf file, specifies:
BLOCK INTERCLOCKDOMAIN PATHS
The design two main clock domains are 100Mhz and 125Mhz so I expect them to drift through phase relationships that violate cross-domain se... |
H: Atmega 328 uart program: compiler error on undeclared variable on register name ending with "n"
I'm trying to get the atmega328 to communicate over serial port with my pc. I'm using hyperterminal to echo back the keyboard character entries. I'm using the max3232 chip to do the communicated with the computer.
When ... |
H: Where does the Maximum Emitter-Base Voltage come from?
The datasheet for a BD679 transistor lists amongst the absolute maximum ratings that the "Emitter Base Voltage" has a maximum of 5v.
This figure confuses me - my mental model of a (BJT) transistor has the path from the base to the emitter equivalent to that of ... |
H: Why do ICs often have multiples of the same configuration, with different part numbers?
Take the SN54AHC125/SN74AHC125 tri-state quad buffer, for example. Data sheet is here: http://www.ti.com/lit/ds/symlink/sn74ahc125.pdf
Refer to page 7, and you will see this (snippet):
Click here for a larger version
SN74AHC125... |
H: wireless door opening detection
I need to find a way to detect when a door is opened and i want to register that through a wifi connection. So the 'door detection' module should send data to a PC over wifi when a door is opened.
There may be better solutions to get this working, but the first thing that came to my ... |
H: Uses for a Double Diode?
Can anyone tell me what a 'double diode' is used for? For example, a BAV99. I'm not sure of the correct name for it and so can't find it in any of my reference books. I've come across one in a circuit, between an output pin on a micro and an input clock pin.
AI: In the case you show the dio... |
H: How to measure battery voltage from a microcontroller
Today I had an interview, there they asked me, if given a microcontroller and Battery then how do you measure the voltage level. Write the steps from scratch with pseudo code.
How can this be done?
AI: If they were after the pseudo code then that was a bad quest... |
H: I2C: 3.3 V and 5 V devices without level-shifting on 3.3 V bus?
Do I really need a level-shifter if I use 5 V-powered devices on an I2C-bus that has pull-ups to 3.3 V?
In my understanding the devices will only pull the lines (SDA, SCL) low (to ground) and never drive their supply-voltage to the bus. So I don't see ... |
H: Why is Embedded Strictly C/C++
I didn't like this question since it can't be easily answered but perhaps I can rephrase:
"What keeps Embedded from changing languages?"
For instance, we pretty much see C/C++ for embedded (I think i've heard ADA mentioned before too? correct me if Im wrong)
But what exactly keeps the... |
H: Can I safely use a HDD in a car?
A few months ago I bought some new speakers and an amp for my Jeep. I made a little face plate with an ALPS potentiometer to control the volume and it has an iPod dock (no head unit, just the pot).
A couple days ago I finally was able to order a Raspberry Pi, and I want to make my... |
H: How to measure pulse width of an IR signal using an 8-bit PIC?
My friend and I want to design a universal learning remote controller, like this one, for learning purposes. What we want to do basically is store and replay infrared pulses.
We want to detect 36kHz, 38kHz and 40kHz signals. A 40kHz signal will have a p... |
H: What capacitance should be added over the inputs and outputs of a voltage regulator?
Is there a nice rule/formula for this or do we always need to go off of the datasheet? I read today (in a datasheet, no less) that the capacitance should be customized for a given application (no further explanation provided), and ... |
H: What is the DONE_cycle startup option?
In ISE, it is possible to select various "Startup Options" for the generate FPGA image by right-clicking "Generate Programming File", selecting "Process Properties", and then clicking "Startup Options". The listed startup options are:
StartUpClk
DonePipe
DONE_cycle
GTS_cycle
... |
H: 3rd lumped circuit abstraction postulate
So i was reading Anant Agarwal's book Foundation of Circuits and stumble upon this postulate
"Operate in the regime in which signal timescales of interest are much
larger than the propagation delay of electromagnetic waves across the
lumped elements"
"The signal timescales ... |
H: Verilog: XOR all signals of vector together
Say I'm given a vector wire large_bus[63:0] of width 64. How can I XOR the individual signals together without writing them all out:
assign XOR_value = large_bus[0] ^ large_bus[1] ^ ... ^ large_bus[63] ?
I'm especially interested in doing this for vectors where the width ... |
H: Alternatives to SPI because of EMI
I currently make a system consisting of a plastic enclosure which contains an MCU talking to 7 ADCs using 2MHz SPI over wires about 5cm long.
The problem is that I'm concerned about EMI. Everything I have read suggests that any kind of digital signal that's not safely on a PCB i... |
H: Classification of VDD and VSS pins
I am creating a library component for KiCAD using a convenient online app at: http://kicad.rohrbacher.net/quicklib.php. The component I am making is the Microchip PIC24EP512GU814 in LQFP http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en554337.
The app asks me to assign... |
H: Capacitor in series and parallel to diagnose APC Smart UPS 1000VA
Brother having APC Smart UPS 1000VA and I noticing high pitched buzzing noise coming from UPS: I think it from power filter capacitor - tall one you see on LHS of picture:
(Picture all sourcing from http://www.elektroda.pl/rtvforum/topic843513.html,... |
H: What does NOM stand for in a datasheet and what does it mean?
The question is in reference to: http://www.ti.com/lit/ds/symlink/sn74ls00.pdf
AI: NOM = Nominal, that's the value you normally can expect, and what the device is designed to.
Note that nominal values are often not the best to calculate with. If you wa... |
H: How to add temperature control to a soldering iron
I see lots and lots of builds of "temperature controlled iron" that simply either:
adds a timer to an uncontrolled iron
adds a dimmer to an uncontrolled iron
The first is the same as turning on the iron later. And the second is the same as paying too much for a 2... |
H: DAC: What waveform should I expect when ramping up?
I have a 14-bit DAC, the AD9775BSV. Ramping the data pins linearly from the minimum of 0x0 to the maximum of 0x3FFF I see (using a scope) the analogue output voltage behaving as follows:
In the first half (from 0x0 to 0x2000), the voltage ramps from 1V to 1.8V.
I... |
H: What analogue input voltages does this ADC understand?
I have a 14-bit ADC for which I do not know what the "accepted input voltage" is.
The datasheet specifies that there are "out-of-range" signals, but I cannot find what the range is. What is the range of my ADC?
AI: From what I can understand from the datasheet,... |
H: Designing my own Bus
This question is further to my previous question: Alternatives to SPI because of EMI. I am toying with the idea of designing my own communication bus. I would be grateful if someone could cast their eye over my preliminary design, and tell me where I'm crazy...
I am currently using 2MHz SPI car... |
H: How to analyze a display?
So while walking around school today I found a neat little piece of hardware thrown in the trash. After a quick overlook, I noticed that the display was one of those 32 segment kinds (like a speak and spell). So I took it apart and starting running some basic test and looking up things on ... |
H: connecting devices with two different power supplies
I wanted to know if this configuration is fine with two different grounds. the microcontroller is powered up with 3.3V and the transistor is powered by 5V. Both grounds are separate.
My question is whether it is safe to connect the microcontroller pin to the tran... |
H: dying battery, increasing resistance
this is a graph of v-i relationship of a battery (not ideal one since it has internal resistance)
as you can see, the slope is 1/R, so as time passes by, R increases, therefore, the slope approaches 0. the graph now tend to become horizontal in time, so the open circuit voltage... |
H: Is this ADC circuit safe for when my Pro Micro is off?
I have the following little circuit:
This voltage divider is used by my Pro Micro to detect when CB_VCC is powered. CB_SENSE leads to an ADC pin on my Pro Micro.
Is this circuit safe for when the Pro Micro is off, but CB_VCC is powered? I'm dealing with 3.3V (... |
H: Best way to connect a RS-485 device
I have to control a device with a C++ application (Windows) via RS-485. I'm wondering, which would be the best way to connect it. Should I use a USB-RS485 adapter (which would be the most flexible solution) or a RS232-RS485 adapter? Any other recommendations?
I am especially conc... |
H: Muscle wire considerations
I am in the planning stages of a project for my new son/daughter, who will be arriving in December. The project involves using muscle wire to make bug or bird slowly flap it's wings. The form will be made of fabric or foam.
Has anyone ever worked with muscle wire, and have some advice or ... |
H: How does the QTR-8RC capacitor charging works?
I would like to understand how does work the polulu Reflectance Sensor internally. I can make it work but I would like to know what is happening electrically.
http://www.pololu.com/catalog/product/961
This is the schema (focus on the bottom left part, the squared area)... |
H: Measure power supply ripple with Rigol DS1052E
I recently received (as a birthday gift) a Rigol DS1052E oscilloscope. I read about oscilloscopes but I never really used one.
So my question is:
How can I measure the ripple voltage of a floating linear power supply, using this oscilloscope?
Can this be done with t... |
H: What is the difference between these resistors?
Take a look at these two different resistors:
Fig.1 source
Fig.2 source
The first one looks "normal" to me (the way resistors I've always bought in the past look..), but the second looks kind of odd. Both of these pictures are of 5% carbon film resistors.
What's the... |
H: Sixteen 100v isolated power supplies
I need to create sixteen isolated power supplies on a single PCB.
Input voltage 9v DC.
Output voltage 100v DC.
Output current 10mA each.
No precise regulation needed.
Efficiency not terribly important.
I was thinking that maybe I could just wind my own transformer with one pr... |
H: C++ microcontroller/processor selection
I am having trouble selecting a microcontroller/processor for a robotics project in C++. I have a program working on my computer that is 1.5+ KLOC and relies on data in twenty other files to function, so please do not suggest I use another language. I tried translating it to ... |
H: How do I calculate the proper width of a copper trace based on a given gauge (AWG) of wire?
I am designing a PCB which I will etch at home, but I need to know how to convert a wire gauge into the proper corresponding width of a copper track on the PCB. Is there a standard formula for this?
AI: There are formulas a... |
H: What are sacrificial components?
The circuit diagram of a board I'm working on has parts labelled as "sacrificial components". These components seem to be pairs of probe points connected via a capacitor, and connected to nothing else.
What are these "sacrificial components"? What are their purpose?
AI: To elaborate... |
H: Can acrylic latex spray paint be used as a DIY solder mask?
I have recently begun etching my own circuit boards for miscellaneous Arduino projects and I need to apply a solder mask so that my copper traces don't oxidize.
I bought this acrylic latex spray paint for a different project, but I am wondering if it could... |
H: WiFi Signal Boosting
a couple of days ago I had a discussion with a colleague when he told us he purchased a "WiFi Booster Adapter+Antenna". It was claimed that by plugging it in his USB and using it instead of his built-in WiFi adapter, he'd be able to connect to those "far away wireless networks".
My assumption... |
H: gate current direction during turn-ON of P-channel mosfet
In a lecture, my instructor told us that mosfets have various capacitances associated with them. eg for a switching application the important ones are- Gate-source cap, Drain-source cap, and Gate-Drain cap.
Now he said that during turn-ON of a mosfet a c... |
H: What are the pins?
I'm looking at a motor controller, the Motor Driver 2A Dual L298 H-Bridge, and since I'm pretty new at this I'm wondering what the pins are:
IN1, ENA, IN2, CSA, IN3, ENB, IN4, CSB
Now, I'm guessing INx stands for INPUT. But what type? Analogue or digital?
AI: The answers are in the datasheet:
... |
H: I can't use digital ports with my raspberry pi?
I have a raspberry pi that I really want to be able to control some motors and was thinking of this one at sparkfun: http://www.sparkfun.com/products/9670
The problem is that the Pi does not have digital ports? And the motor require it for control (low/high signal). I... |
H: Maximum input frequency of 74HC Logic gates
I have a clock that is running at 25.175MHz I want to run that signal through some basic logic gates from the 74HC series.
I have looked on the datasheet for the 74HC08 (AND Gate), I can't seem to find any information about the maximum frequency i can run through these g... |
H: Why is the voltage regulator's output current not what I'm expecting?
I've recently bought a couple of Sanyo LA5003 voltage regulators (datasheet). From the datasheet, I understood that the highest possible current on the output can be 60mA. However, when I connect it to several (2 or 4) series-connected 1.5V AA ba... |
H: Power supply design pattern with various capacitors
I'm seeing the following pattern for power supplies on the board I'm working on:
What is the purpose of the capacitors? Why are they of different values? What is the purpose of the design pattern?
AI: stevenh already said it pretty good, but most likely they are ... |
H: While loop optimized away
I have the following code in my microcontroler program:
// Wait for ADC conversion to complete
while ( ( ADCSRA && _BS( ADSC ) ) == _BS( ADSC ) ) {}
Where ADCSRA is a register that will change its value once an analog conversion is completed and where I want to wait for a bit to be clear.... |
H: Raspberry PI without OS on it?
I've been doing a lot with Arduino recently. It's very simple because you can directly execute C++ code on it without the need of operating systems or drivers.
I've done some research and AFAIK, you usually install Linux on the Raspberry PI and create python scripts or C++ binaries on... |
H: How can I instruct my compiler to use 8 bit bytes instead of 16 bit integers?
I have the following code in my microcontroler program:
int analogValue = ADCH; // ADC Data Register
//
// Simple analog comparator.
// If analogValue lower than threshold then toggle output high,
// Otherwise toggle it low.
//
i... |
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