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H: Why is ground shared between primary and secondary side in LT3750 circuit example
LT3750 is a capacitor charger controller IC. The sample (typical application) circuit in its datasheet shows an otherwise isolated secondary side sharing a ground with the primary side. A PCB layout suggestion for the same circuit lat... |
H: crypto benchmarks STM32L4
Can someone give me an indication on the performance (time) of ECDH executed on the STM32F4 board. The STM32F4 has hardware acceleration for ECC (http://www.st.com/st-web-ui/static/active/cn/resource/technical/document/user_manual/CD00208802.pdf) but I can't find any benchmarks.
[backgroun... |
H: Does input offset voltage for amplifiers remain almost same
In Op-amp datasheets, input offset voltages are specified. Does this input offset voltage remain same (no significant difference) for each IC or can it change significantly each time I use the device? e.g. if the offset is defined to be ±1mV in datasheet a... |
H: Heat Sink Isolation
What is the best strategy for heat sinking a MOSFET? I have a heat sink all picked out here. I also have a MOSFET picked out here. I know that the tab is electrified with the drain. There are a few choices on how to electrically connect the MOSFET to the heat sink.
Set the heat sink to the sam... |
H: Need to find the component with marking 500
I am having hard time in finding what this component is . It has 8 pins and a marking on it says 500. It has 2 pins on bottom on each side and two on each top side.
On the board 2 pins on left bottom are as inputs and two on the right are used as outputs.
I searched for ... |
H: Use diode to drop down voltage from ~3.7V for nRF24L01
I have a RF module (nRF24L01) and Li-ion battery with 3.7V nominal voltage, so when it is fully charged it can be a bit higher than 3.7V (I guess).
RF module can work from 1.9V to 3.6V and draws <13mA. I know about LDO regulators, but I don't have such, rather... |
H: Will this phototransistor circuit work?
I'm building an 8 stage coil gun for a physics project, and I want to verify this circuit as I've never used a phototransistor before and I'm still pretty new to mosfets. Here is a schematic:
The idea is that when the projectile (a penny in this case) crosses between the ir ... |
H: STM32 ADC conversion using HAL
I am trying to learn how to use "new" HAL library from stm32.
When I try to do simple ADC conversion it works just one time, but then it stops converting. I suppose End of conversion flag does not get set. I am using STM32f429I Discovery board, which has STM32f429ZI on board.
Note tha... |
H: Having trouble with light activated circuit.
R1 = 10K 1/4W Resistor
R2 = Photoresistor (any type)
R3 = 2M2 1/4W Resistor
R4 = 1M 1/4W Resistor
C1= 10µF 25V Electrolytic Capacitor
C2 = 100nF 63V Polyester Capacitor
D1 = 1N4148 75V 150mA Diode
IC1, IC2 = 7555 or TS555CN CMos Timer ICs
BZ1 = Piezo sounder (incorporat... |
H: Input Impedance Question
As I look at the Datasheet of a differential amplifier for input impedance, i see below statement.
0.8||2 for Differential.
0.4||2 for Common mode.
What does GΩ||pF mean?
AI: Input resistance, expressed in GigaOhms; in parallel with stray capacitance, expressed in PicoFarads |
H: When to use an active filter instead of a passive filter?
I want to build a low-pass or a band-reject filter to remove 50/60Hz humming noise. I couldn't decide where to start with. I will use this filter to remove 50Hz noise where I make data-acquisition of a signal through a BNC cable.
Active or passive filters b... |
H: Circuit changes, what is the input high and low given when the circuit is lit and not!
One change in the circuit, the R1 is not 4300 ohms but instead 4700 ohms.
The voltmeter is the input into the raspberry pi GPIO board. What would be the input (voltage) when light gets to the phototransistor and when not?
PT0 is... |
H: bc 547 and bc 548?
I was doing a 3*3*3 arduino cube project when this doubt struck me.
Some instructables I watched used 2N3904 transistor whereas a few used BC547.
I hava a 548 at hand and was thinking whether I could use it. I use a variety of leds - red,blue,green and yellow. So current may range between 15 ... |
H: STM32F3 Discovery + GNU ARM plugin + OpenOCD - cannot load the binary onto the board
I'm using the GNU ARM plugin for Eclipse with Open OCD as a debugger. This is on Windows 10 x64. The problem I'm facing is the following error when trying to debug or run the sample program:
Error in final launch sequence
Faile... |
H: Why do we need to install a power transformer for each high building?
I live in area where many high buildings are being built. Each building is more than 10 floors. A special room is made next to the main entrance or the garage. The room is designed for installing a power transformer inside it. The room also provi... |
H: Switching multiple outputs with a single input
Here's my problem. I need a way to switch between two inputs of four signals each (four 5V lines and 4 3V3 lines). They need to be switched together, and ideally with a single jumper or an electrical signal. I know there are many ways to accomplish this (e.g. by 4-sets... |
H: Can an inductor be substituted for a coil
I am designing this FM receiver circuit.
I have a few questions related to the circuit.
Buying coil in my locality is a little expensive. So would it be alright to substitute an inductor in its place? If yes, would it be alright to use a 0.2 micro-henry inductor? And al... |
H: How is the output voltage of a mobile phone charger fixed to a rated value?
Here is the circuit of cellphone charger. I have seen the input voltage range for a cellphone charger to be 100-230 V but the output voltage to be fixed to the rated value(like ~4.5 V). So, my question is how the output voltage is fixed to... |
H: DC blocking capacitor in opamp feedback loop - does this count as the "signal path"?
I'm a bit new to electronics, so this may be a dumb question, though I hope not.
I'm working on a pre-amp circuit which can drive several TDA7492 boards from a single source (I've found they don't enjoy all being connected directly... |
H: What type of switch is only on when released
I have a situation where I've got a few electronics boards stacked on top of each other. I don't want the boards to be powered when stacked but when they're no longer on top of one another I want them to turn on. I figure a push switch that is off while depressed but on ... |
H: "Break-before-make" SPDT Relay out of 2 SPST Relays
I require a SPDT relay (changeover) that will switch up to 600Vdc, which presents some problems because on the major suppliers such as Digikey, such a product is not readily available at such a high voltage.
However, there are SPST relays available and I was think... |
H: FPGA pin assignment for BGA fanout
I'm working on a project that involves multiple (many) BGA packages, namely interface converters such as Ethernet PHYs connected to a central FPGA.
I've already worked out a (tentative) layer stackup in terms of what signals will run over which layers, but I need a good strategy ... |
H: Calculate simple NPN transistor circuit Arduino 3.3V
I am trying to control a 3v latching relay (single coil) using an Arduino @ 3.3v [SPST-NO PCB Mount Latching Relay, 16 A, 3V dc] rs-online.com/web/p/latching-relays/8276283/
The relay requires a 3v positive to latch one way, and inverse to latch the other way.
... |
H: Battery configuration for 5V
I am building board with Atmega328p, in total energy usage is 40mA, now I need to focus on power suplay, on the board is standard V regulator to 5V, what is better baterry configuration, 4 AA which gives me 6V, or 6 AA which gives 9V ? I need optimize space so 4AA would be better, but 6... |
H: FPGA Frequency divider with linear regulation
I'm currently developing an FPGA gateware requiring a regulated frequency divider and I wonder if there is any tricky way to get a linear output frequency regulation?
What I mean is that if I use a simple preloaded counter I get a f~1/x relevance, where x is a counter i... |
H: Why this pair of IGBT's died silently?
Before some days I have taken a look at circuit which controls AC current's frequency. That circuit was a VFD which looks like:
simulate this circuit – Schematic created using CircuitLab
But this circuit is for controlling 3 Phase motor.
So, I tried to make a similar one that... |
H: JTAG connector - large pitch to smaller one
I have a Segger's Jlink EDU probe which I used for debugging and programming various ARM based MCU's. But now I have to work with this LPC4088 QS board which has a smaller pitch 20-pin JTAG connector that usual one. So I am searching for something like this:
to transfor... |
H: Time delay dpdt relay using only pot, relay, and cap (discreet components and no transistors)
I am trying to design a simple time delayed relay circuit that uses only a potentiometer, 5V dpdt EM relay, a single sufficiently large capacitor, additional resistors (if needed), and buttons/switches, powered by a 9V bat... |
H: Connecting Sensors To A Production PCB
Background: I designed a simple board a while ago using a ATMEGA328 and a ESP8266. The idea is that the ATMEGA deals with sensor data and the ESP8266 deal with the whole online bit.
I did a initial run of 20 prototypes when a client of mine showed interest in the board and dat... |
H: PN junction voltage drops in a Saturated BJT
Let's say we've got our BJT operating in its saturation mode. Can we make (a rough) approximation now and make calculations for the circuit assuming that both Ube=0.7V and Ubc=0.7V (for an npn). Or do these values change in sat mode?
AI: If a NPN BJT is operating in the ... |
H: Are ratings (volts and amps) inter-changable on components?
Assume I have a component, it is a flip switch (like so), on the switch it states, 120V at 3A or 240V at 1.5A.
Following this pattern, is it safe to assume the switch is capable of servicing in an environment with 5V at 72A?
Also, when does 5V become unsaf... |
H: Please suggest me soldering station
I want to buy soldering station. Can you suggest me some?
I don't want to buy some very expensive station (like Weller), but I don't want also some cheap station. I will use it firstly for some "basic" soldering and then for SMD. What do you think about Hakko FX888?
Here is one o... |
H: Does a carrier wave need to be sinusoidal?
I am trying to AM modulate a song and I have an idea of how I am going to do it, but I need a carrier wave to start with and I've been having trouble creating one with a ceramic resonator because I don't have a CMOS inverter.
So I thought I would go shopping for an IC chi... |
H: Auto snap to the selected component when press "M,S" in Altium
In Altium schematic editor, select one component, and press "M", then "S" (move the selected object), when you press the mouse button now(anywhere on the sheet, even not on the component), the cursor will snap to the component automatically. But in PCB ... |
H: Comparator question for weak sine inputs
I have the above circuit to convert mV level sines to pulses. It is a working design I just simulated it.
When input sine signal VG1 amplitude is less than around 70mV comparator cannot convert to pulses. When the input sine amplitude is more than 70mV it can successfully c... |
H: What is the meaning of fault_reg = ram [address] in verilog?
input [3:0] address;
reg [3:0] ram [7:0];
reg [3:0] data, fault_reg;
fault_reg = ram[address];
data = fault_reg;
If the value of ram is 1010 and the value of address is 100, what is the value of data[0], data[1], data[2] and data[3]?
Does it mean data[0... |
H: FPC connector to DIP
I have a board which is something like this:
(available on eBay)
I know I have to buy a socket, but how do I solder the connector onto the board?
AI: You solder it with steady hands.
Its just the solder holding it in place?
Solder would be enough to hold the connector, if you are gentle wit... |
H: High Temperature Conductor in Air
I am trying to determine what the best material is for a high temperature conductor. It is for distributing power inside a furnace. I need to run at around 1000 celsius (the furnace is hotter but this is how hot the conductors might get). The lower the resistance, the better. Plati... |
H: Do processor commands and values have binary codes?
I am working on a diy computer and I am struggling to understand how processors handle information. I would like my diy computer to be able to do the bare minimum, for example calculator, output text. But since I will only be using commands in binary, do I have to... |
H: Switch (Relatively) High Voltage from Logic Level
The Situation:
Basically, I would like to switch a load that requires 30v using a switch that cannot have more than 5v across it. More descriptively, I am trying to drive the anode of a VFD segment from the output of a shift register (probably a 74HC595).
What I Ha... |
H: Feedback resistance condition (Rf > 29R) in Phase-shift oscillators
In an equal resistance , equal capacitance CR phase-shift oscillator, the feedback resistor has to be slightly larger than 29*R
When I am attempting to simulate the circuit at 29*R, there's an oscillating transient response but it is not ... |
H: Is it illegal to transmit in the FM range for personal use
I am building an FM transmitter. It is going to be designed to transmit only for a short range of around 50 to 100 meters. My question is whether it is illegal to transmit signals in the FM band over this short range without owning a license? If yes, what s... |
H: How to verify the reliability of torque rating of DC motors given on online sites?
I have to decide the motors to be used for my robotics project, but while searching for the DC motors I have found out a rather unusual fact that I can find several motors who provide the same torque while there is a significant diff... |
H: Is there any science (or trick) to determining a replacement op amp?
I have a "mature" circuit design that calls for an LF411 op amp. I've built it up with a through-hole PDIP and it works just fine. Now I'm designing an SMD PCB for the circuit so I have the opportunity to review the device selection and perhaps ch... |
H: A NOT gate with gradual changes between state
I have a simple NOT gate circuit with the following arrangement.
LED D1 will light up by default. If I push SW1, the transistor Q1 will activates and D1 will be turned off. This NOT behaviour works just fine.
The problem is, I want D1 to turn off gradually (the gradati... |
H: Does "POLY-MET" unambiguously describe a capacitor type?
I have a BOM where one of the capacitors is described as .33UF 250V 10% POLY-MET.
I did a search on the term "poly-met" and found a Cornell Dubilier device with that particular designation. It's a metallized polypropylene capacitor, which makes sense of the n... |
H: Why do multimeters have an aluminium foil at the back?
I was wondering what is the purpose of aluminium foil at the back of some multimeters? I did a continuity test and found that it is connected to the ground (COM) terminal.
My initial guess was that it was some kind of shield but since it wasn't fully enclosed a... |
H: EAGLE change name of wire label in all similar label
I've some schematics with, for example, a power wire with name VCC. I need to change this name to USB_VCC on all wires which have by name VCC. Since I've a lot of wires with names to change, there is a function in EAGLE that allow me do somethig like: "Change all... |
H: Sine to pulse converter circuit help
I have a sine to pulse converter box(LM2903 is used), it works very well and I also have the circuit schematics. The converter converts the mV level sinusoidal signals to pulses.
I want to rebuild it so first I drew it in LTSPICE but it doesn't work. It outputs constant negativ... |
H: Good book references for physics and math for electronics
Next year I'll join an engineer school in Dijon, France in the field of Electronics (Embedded Systems). I am currently taking a 2 years general IT education and my main problem is that I am very bad in math and I have no real basis in physics. So I'm wonderi... |
H: What is the equivalent resistance between Nodes A and B in this infinite resistor network?
Please provide analytical solutions or instructions and not simulation results.
Thanks.
simulate this circuit – Schematic created using CircuitLab
AI: The horizontal resistors have no current in them because the circuit is s... |
H: Data encoding for GFSK wireless
We are designing a RF link (2GFSK) using the CC1125, to replace and older system.
The older system uses NRZI data encoding with bit stuffing.
Bit stuffing is used to remove the present of stop flag (0x7E) data and to avoid having too many 1's in a sequence.
An older RF engineer told ... |
H: Why are the three component LEDs in an RGB LED so unbalanced?
I was recently spec-ing some RGB LEDs for a project, when I noticed that the millicandela ratings on the three colors are rarely close to the same number. (i.e. 710mcd Red, 1250mcd Green, 240mcd Blue).
Does this cancel out somehow, or does this mean that... |
H: Is there a latch / flip-flop with this behaviour?
I've looked at the most popular flip-flop types, and none of them seem to have this desired behaviour:
It would have two inputs: A set signal, S, and a data signal, D.
If the set signal is true, it would save whatever is in the data input. However, if the set signal... |
H: Behaviour of capacitor discharging through a transistor's base
I have the following circuit which attempts to turn on and off LED in a gradual manner (instead of having abrupt change between states).
So when I press S1, LED1 will light up gradually, thanks to C1's charging. My eye can observe a 1 second period til... |
H: How to bias BJT using Widlar current source?
Here is Widlar Current source driving load:
It gives almost constant current for wide range of load resistances:
Here is one circuit involving BJT:
You can see it is biased using one voltage and one current source.
My question is, how I can use Widlar current source t... |
H: Confusion about solar cells and MPPT
Pardon the potentially silly question.
I have been reading about photovoltaic (PV) cells and max power point tracking (MPPT). From what I understand, a MPPT module can use a DC-DC converter to change the voltage on the PV's terminals to its corresponding MPP voltage (Vm). My q... |
H: Running Nokia 5110 with 3 pins
I recently received a Nokia 5110 LCD screen and have hooked it up to my Uno and got it displaying stuff.
I'd like to try using it in a project with an ATtiny85 and found some resources to that effect, however, I'd like to be able to run it from fewer pins than the 5 I've started off w... |
H: Storing the charge from a MOSFET Bridge Rectifier
I am using the following MOSFET Bridge to harvest AC bursts, that come from an electromagnetic transducer.
In front of this circuit is a supercapacitor I have added.
I read the following on a webpage that talks about this design:
One caveat of the FET bridge circu... |
H: What is the best way to measure voltages higher than the ADC internal reference?
Let's say an ADC has an internal voltage reference and I want to measure voltages greater than that reference. I can use a voltage divider on the input(s) to limit my max input signal to said Vref. Now let's assume the ADC allows for a... |
H: Maximum output current OpAmp
simulate this circuit – Schematic created using CircuitLab
This is the circuit schematic of an astable multivibrator. I have to chose the resistance value of R3 in order to limit the output current of the OpAmp. The OpAmp model is TL081 Texas Instruments, and this is the link to its d... |
H: DRAM timing with row and column decoders
Consider a 64Kx1 DRAM memory which means the number of rows is 256 and the number of columns is 256. In other words, two 8x256 decoders are needed for selecting the right row and column.
Since, each memory location is 1-bit wide and we usually read 8 bits. Does that mean wi... |
H: Perfboad question
I am still confused about working with perf board and solder. but I want to ask, this question:
When adding 2 electronic element on a perf board, in series, the start point of element 2 should be in same line of the end point of element 1, horizontally, or in the same vertical line?
AI: The answer... |
H: How does the internal resistance of oscilloscope compare to that of the DMM?
Both are the instruments that measure voltage, so what are the difference between multimeter and oscilloscope in terms of their internal resistance ?
AI: Oscilloscopes tend to have standard input resistances such as 1M in order to be compa... |
H: From DTFT to DFT, why do we take N samples in frequency domain
In this post:
Why does frequency equal k/K where k=0,…, K-1 in Discrete Fourier Transform?
And I have read several books, the authors take N samples with DTFT to get DFT. Why N?
I think N is simply the sampling rate in time domain, right.
In frequency ... |
H: What type of connector it is?
Can anyone identify this connector type?
It sticks out of my wall near television area. I suspect it may be some kind of antenna connection, but I'm not sure. Could not find it in any of the antenna connectors listings.
AI: From the look of the wires, I'd say that they are a speaker ca... |
H: SiGe/GaAs RF MMIC as photodiode preamp
Could you suggest if it's possible to effectively use SiGe/GaAs RF MMIC (which have 50 Ohm input impedance) as first stage of photodiode amplifier?
The idea is to reverse bias diode from some +50V, and connect it directly to MMIC input, so that photodiode is loaded to MMIC's ... |
H: Is capacitor reactance [sometimes] defined with negative sign?
Wikipedia currently claims so
but I've looked in 6 books via Google Books and it's not defined like that, i.e. it's just
$$ X_c = \frac{1}{\omega C} = \frac{1}{2\pi f C} $$
Is Wikipedia full of nonsense on this, is that just a fringe def, or somehow al... |
H: Method of generating a random binary number using gates
I was wondering how a computer or any other device can generate random numbers. Is there a way to do this using only digital parts(non-programmable parts such as gates)? When I think of it, it seems like there has to be an "analog side" to generate random numb... |
H: Op Amp Integrator Circuit - Why is there a linear current and voltage for a short time before exponential values?
Consider the following integrator circuit:
Why doesn't the current through the capacitor and voltage across it behave exponentially? There is a straight section in the beginning, up to around 2ms - why... |
H: 3 watt LED plus LiFePO4 battery (1 cell), no resistor, no regulator. Is there anything wrong with this?
I read that you should "always" have a resistor in series between an LED and its power source. But what if the power source already has its voltage set to a suitable max for that particular LED? Why would you n... |
H: Low level sine to pulse converter with sharp rising-edges
I have two circuit simulations: Circuit1 and Circuit2 which are shown in above schematics. For the sake of simplicity I drew them in the same schematics. They share the same 12V voltage source and the same signal input VG1. VF1 is the output for the Circuit... |
H: Can one tri-state pin drive two SS pins?
This is how i see it;
State H: SS out is High, Deselecting SS 2, turning off Q2 and on Q1, which grounds SS 1, turning it on.
State L: SS out is Low, turning off Q1 and grounds SS 2 through Q2. SS 1
is deselected by R1
State Z: SS out is high impedance. R1&3 keep the SSs hi... |
H: Guitar Pedal not functioning at all, no sound created
Ok, so I'll do my best to explain my situation. (FYI, I am a beginner)
I'm building an overdrive pedal for a school project which I plan on modding with the help from a teacher. However, I thought I did all the steps correctly but when I plug it in, it just kil... |
H: Digital Circuits Analysis
Does anyone understand where 2.5v , 10 v, and 5V ( highlighted in yellow) are coming from? I know that Vcc=5V, and the two resistors R1 and R2 are in parallel so Req=0.5Kohm, and the voltage divided by 2 which makes it 2.5V . How did they find IE=2.59 mA ? Also, if you can explain the obta... |
H: How do I determine the courtyard for a component footprint?
I'm using KiCad to lay out PCBs for some projects and often I find I need to develop a new footprint or tweak one that's in the library.
I'm able to determine most things I need by consulting the datasheet and occasional other sources, but I haven't found ... |
H: IP Core Generator fails with Error
I'm working on a project using a Spartan-6. I created a FIFO with the IP Core Generator (New Source -> IP Core -> FIFO -> Generate). The LOG looks like this
The IP Catalog has been reloaded.
Qt: Untested Windows version 6.2 detected!
INFO:sim:172 - Generating IP...
Resolving gener... |
H: Ethernet switch controller chip
Recently I bought an ethernet switch controller based on the Realtek RTL8305NB chip. It was bought as a proof of concept for my robot. Unfortunately, the board is too big and I want to design my own 2-layer PCB (also to learn new stuff). I would like to use the same chip, but finding... |
H: unfamiliar gain equation of differential amplifier
I am examining op amps and I found this pdf very helpful: http://www.aicdesign.org/SCNOTES/2010notes/Lect2UP230_(100327).pdf
In this tutorial, the op amp circuit topology is given as this:
and gains of stages of the op amp are given like this:
First time I see ... |
H: Are MOSFETs better for high power applications than the BJT?
I was reading that the MOSFET is more optimal for high power situations at low to medium supply voltages than the BJT. However, I'm questioning this, because MOSFETs and BJTs waste little to no power while off.Mosfets are more pro... |
H: Accelerometer on doors and windows
We have made a mistake. We created this pcb with accelerometer , a very good one (ADXL345) datasheet here and it sleeps ,and waking up on acceleration event. in our case we set it to almost the minimum possible of 124mg thresh .
What happens is that it works great almost for any t... |
H: How to record electrical signal through PC sound card as an audio file?
I am doing some study on the frequency of electrical supply. I need to do the analysis on MATLAB. I want to record the electrical signal as an audio file in my laptop.
As I am a beginner working with 220V mains, I have a fear of busting my s... |
H: Calculate VA for a given wattage
How to calculate VA given a wattage say for example 300 watts.
AI: $$VA = \frac{Watts}{PF}$$
where VA = volt-amps, and PF = power factor.
You'll have to find the power factor for the device yourself as you have given so little information. |
H: Assistance with CMOS simulation
It's been a very long time since I took intro level EE courses. I'm working on a hobby project and as a refresher I figured I would simulate a CMOS inverter. For the life of me I can't figure out why the simulation doesn't produce the expected results.
I believe I've faithfully repro... |
H: How to implement programmable Schmitt trigger?
I am trying to build a Schmitt trigger that would allow adjusting High and Low threshold values with a microcontroller.
simulate this circuit – Schematic created using CircuitLab
I could replace R1-R2 with a DAC, but how do I adjust the feedback resistor R3? Is the tr... |
H: Analyzing a circuit using simple voltage division instead of Thevinin's theorem
I can use Thevinin's theorem to simplify R1 and R2, and then use the voltage division rule to get the output. However, I want to do it without using Thevinin's theorem. How to analyze the circuit intuitively, perhaps using some extensio... |
H: Magnetometer- there is no low current feature?
I have gone over all magnetometers available, most of them using I2C, and connected to some MCU, and i couldn't find even one with interrupt.
That means the processor cant go to sleep, and always has to listen to what is going on, there is no interrupt on change option... |
H: What is the name/type for this soldering iron tip?
I got a old soldering iron, I'm trying to find the replacement tip but I don't know what to search for. When I search soldering iron tip it only show the hakko style tips. Can someone help me identify this tip?
AI: There are a few of these available from an Ebay se... |
H: Testing parallel IGBT module
A single NPN IGBT chip can usually be tested by a 9V battery between gate and emitter.
However opening up a larger module reveals many IGBT modules in parallel. I`ve seen some inverters using several of these in parallel again, together maybe 200 IGBT chips in parallel for a single pha... |
H: Possibly Incorrect Current Reading
I'm not entirely sure if I have done the following equation correct or not, but based on the calculations, my multimeter result seems to be incorrect. I have a very simple circuit, containing a 9V battery, an LED (with 3.2 V forward voltage at 24 mA), and a 270 ohm resistor (as sh... |
H: Which instrument for arbitrary signal commutation (matrix)
I would like to test a bunch of sensors. Each sensor has a DB15 connector with mixed digital and analog signals (bw ~5MHz, Z ~120R).
I am looking for an instrument where I can control which couple of sensors I would like to interconnect to the measurement ... |
H: Currents confusion in a JFET datasheet
I am analyzing a JFET. The datasheet has both information about the currents Igss and the maximum of Ig. I know that the Igss is a the reverse current in the PN junction but I can't explain myself what kind of current is Ig and when does it flow?
AI: The maximum value (Ig) is ... |
H: What is the point of converting everything to NAND/NOR and how do you do it right?
The title pretty much says it all. I know that A' + B' = (AB)' is the basic transformation needed to do so (at least for NAND gates), but whenever I apply this I feel like I'm doing it wrong. For example:
C' + AB' + A'BD'
Here's what... |
H: How to Convert 12Volt DC Automotive Battery Charger to 1.5V
I'm not an electrical engineer of any sort but was wondering if someone wouldn't mind sharing how I could choke a common AC to DC 12 Volt automotive battery charger down to 1.5V output while retaining the amperage that one of these battery chargers would n... |
H: FRDM-KL25z assembly delay loop causes reset
I'm currently working on a project using the FRDM-KL25Z development board and programming using Keil MDK-lite (5.14a). What we're supposed to do is create a simple traffic light using three corresponding LEDs and a push button to expedite the light change(not immediately ... |
H: Is Variable synthesizable (VHDL)?
What I know is Variable has no hardware representation. So does it comes under the category of Non-synthesizable codes in VHDL?
AI: How is a VHDL variable synthesized by synthesis tools has some useful information though it's not exactly a duplicate of your question IMO.
Just becau... |
H: Nixie Tube Voltage Safety
I have seen clock designs like this one:
where the nixie tube leads are not fully inclosed. There is likely 145-170V on these lines. I am just wondering if it's safe to allow the leads to be exposed and what sort of consequences there might be if someone accidentally touches them.
AI: Tha... |
H: Unity gain op amp gives static, incorrect output
I have the circuit shown here:
where I'm using a switching regulator (not the linear 78xx shown) to provide me with 5V to power an Arduino and a little more circuitry that the Arduino is monitoring. The Arduino is measuring (and logging) the voltage at A - ie I'm l... |
H: normally open or normally closed OptoMos
In the following OptoMos datasheet the OptoMos is defined as Normally closed, when there is no input the output is closed.
But in other OptoMos like the SFH618A-2 i can't find if the OptoMos is NO or NC.
AI: The SFH 618A is turned on by LED current - the symbol of the device... |
H: Modern jack-of-all-trades cheap OPAMPs?
I am trying to design my first "big" project, and I have to choose the OPAMPs to use. The problem is that I am feeling overwhelmed by all the possibilities.
I feel tempted to just stick on the LM741 or LM358, but after reading around (i.e. there http://www.electro-tech-onlin... |
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