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H: Power output needed to go through a car
I need to know the power output needed for transmitter if I want that receiver catch this signal? In details, there is a tunnel 4 by 4 meters and a cars in it, cars have a receiver inside and transmitter on the tunnel upper floor. So, when car rides under the transmitter, rec... |
H: Minimum current to measure from a 30kW motor?
We've been troubleshooting a problem here at work and we're kinda stuck so I thought about asking for some opinion from you guys. We have a 30kW 240V 3-phase motor with a rated current of 109A that is driven by a Toshiba VF-A7 inverter. The inverter trips a few seconds ... |
H: How to adjust red brightness on MAX7219 with RGB LED
I want to use MAX7219 (datasheet) to control bunch of RGB LEDs. With common anode LEDs I should be able to use up to 16 3-color bulbs in following configuration:
simulate this circuit – Schematic created using CircuitLab
There would be probably needed a resistor... |
H: avrdude: initialization failed, rc=-1
when trying to program the fuses I get this known error message:
$ sudo avrdude -c usbtiny -p m328p -U hfuse:w:0x05:m
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.
avrdude done. Thank you.... |
H: Is it safe to parallel connect components to a single to a 12v DC PSU?
Prerequisite:
For a home-decor project, we wish to work with different LED strips and even a larger LED chip as a central lighting source by attaching everything to a powerful, high quality 12v CC/CV DC PSU. (eg., Mean Well HLG series).
Each po... |
H: What's the middle terminal in the VN2222 MOSFET?
In the VN2222 MOSFET below (diagram is from PSPICE), what is the terminal with the arrow pointing in? The one to the left is the gate, above and to the right is the drain and at the bottom is the source. What's the terminal in the middle, though? Under what circumsta... |
H: Capacitor and discharger selection for pulse discharging
I want a 100 Joule pulse in 350 micro seconds. I have 1000V nbu 1012 capacitor discharge circuit . In datasheet, Max. average power is 3000 W(page 8), however I need 100/350us= 285kW instantaneous power when pulse is activated. Does the nbu circuit can handle... |
H: Building a 2-bit adder with a propagation delay of at most 2 gates
An XOR-gate itself counts as 2 gates, so if I use an XOR-gate the delay would already be 2.
I have no idea how to do this, as a full adder for one bit already contains 2 XOR-gates (or 1 XOR-gate, 1 AND gate and 1 OR gate) so that would already have ... |
H: 1-wire in ATMEGA1281 problem
Could someone help me with something like this? I wanted to add DS18N20 thermal sensor (http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf) via 1-wire interface and when I'm trying to connect it to ATZB-24-A2 (http://www.farnell.com/datasheets/1738045.pdf), which is using ATMEGA 12... |
H: Switch DEBUG doesn't seem to be working in my code
Following code I tried on EDA playground with command appended with +define+DEBUG but DEBUG switch doesn't seem to be working. Its always block is sensitive to error and this variable is changing four times here but still the block is not being sensitive.
http://... |
H: 8048 movp instruction
I am trying to understand the MOVP and MOVP3 instruction of 8048 microcontroller. Now in manuals no specific, clear example is given. What are the functions of these instructions?
MOVP A, @A--> move program data in current page in accumulator, which locations data is copied here?
MOVP3 A,@A-... |
H: Dot convention in Magnetically coupled circuits
The book says that the for loop 2, the KVL is \$-j3 I_{1} + (12+j6)I_{2}=0\$ , but the loop 2 leaves the dot in its coil. Isn't it supposed to be \$-j3I_{1} + (12-j6)I_{2} =0\$ ?
AI: The dot only determines the polarity of the mutual voltage, it won't affect other di... |
H: Dual GPS Antenna Connection to Positioning Module
I am using a Positioning module that has a SMA port to hot plug an SMA antenna. It also has pins available through its footprint to connect a GPS Antenna.
The module name is SIM908. I was not able to spot a place in its data sheet that describes if both antennas can... |
H: Weird problem when using relays
We have a product which is to do resistance measurement. The simplified schematic is as below. A 50mA DC current flows through the resistor, and we measure the voltage on the resistor's terminals. There are three relays from OMRON, G4W-2212P-US-TV5-24VDC. And because that relay has t... |
H: What is the benefit of using carrier frequency for an amplifier?
I provide the link here:
http://books.google.dk/books?id=wnPNkbJUBxkC&pg=PA153&lpg=PA153&dq=carrier+frequency+of+an+amplifier&source=bl&ots=mtT6SOFuqJ&sig=1AEAPY4Ke3qHhqqatW2S9kybJes&hl=en&sa=X&ei=YJV9VOqvM4TkaJPQgMAN&ved=0CFcQ6AEwBw#v=onepage&q=carri... |
H: Downloading programs from Microcontrollers?
So I'm trying to reverse-engineer a small PCB which has an ATMEGA48-15AT1 microcontroller on it. My question is, can a program, on said microcontroller, be downloaded and read as the C# code that its programmed in (e.g. through AtmelStudio) ?
AI: An AtMega is likely to be... |
H: Is this a true pink noise generator?
I found this neat circuit (page 18/62) but I don't understand it.
This doesn't seem to be your usual white noise generator plus pink -3db/octave filter. Is this a true pink noise generator?
AI: The circuit you reference actually does work by generating white noise and then filte... |
H: Mealy Safety Device with 2 inputs
I have an assignment in college and I would like to ask some questions:
You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are available to enter the combination. An electromechanical interlock guarantees that the buttons ... |
H: Does a 1 watt 660nm LED put out more radiant flux than a 1 watt 630nm LED?
Given two LED chips consuming same or very similar amounts of DC power,
One emitting light peaking at 630nm,
The other at 660nm,
In terms of output of (but light irrelevant to the sensitivity of human eye);
Which one would output more e... |
H: What effect does the drain resistance have on the output voltage of the logic gate?
The logic gate is meant to be a NOR gate, but how does changing the value of \$R_{D}\$ affect the output voltage? Doesn't increasing the value of RD always make Vout lower because of voltage division. The only exception I can thin... |
H: Is there a metal that will not interfere with smartphone reception as a case?
I want to design an iPhone case that will include a metal plate on the back of it. Is there any kind of metal that will not interfere with the phone's reception?
AI: That depends on what you mean by interfere. If you mean as if there were... |
H: Why does the current in autotransformer motor starting gets reduced squared in relative to the voltage?
Say, relatively, the motor's full voltage rating's voltage, current and torque are 100, 100 and 100
Why does when the autotransformer tap is set at 80%, the motor runs at
80 64 64
65% and 50% as follows:
65 42 42... |
H: Why I=(V(in)-V(out))/R in zener resistor circuit
I am a hobbyist electronics student who try to study "The art of electronics" book. I am having trouble understanding below passage from the book?
I am having trouble following what is going on with I = (Vin-Vout) / R part? How do we get that result?
AI: Think of id... |
H: What is the purpose of the capacitor in this transformer circuit?
I a audio DAC output stage I have seen the following circuit.
It's function is to convert an balanced signal to an unbalanced signal.
IN+ and IN- are differential outputs that are biased at 2.5V.
simulate this circuit – Schematic created using Circ... |
H: Analyzing a MOSFET circuit
This is the problem:
And this is my attempt to solve it:
For (1):
I don't know how to get vgs or how to use the hint to get rid of it.
For (2):
I assume that my solution is right but should I add details on how did I get Rout ?
AI: You have an equation for \$v_o\$ of the form \$v_o = kv... |
H: How do I find the Truth Table for Mealy State Machine?
This is a followup to my previous question:
I have this assignment in college:
You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are available to enter the combination. An electromechanical interlock ... |
H: Is analog signal arithmetic faster than digital one?
Would it be theoretically possible to speed up modern processors if one would use analog signal arithmetic (at the cost of accuracy and precision) instead of digital FPUs (CPU -> DAC -> analog FPU -> ADC -> CPU)?
Is analog signal division possible (as FPU multipl... |
H: Dual smart battery design and PCB layout
I have a system that is powered by a 7.4V Lithium-Ion battery. The system, which is a combination of processor module and sensors, draws a varying amount of current at varying voltages (5V, 12V, -12V, 6V...) but pulls about 10 watts. The battery I chose is quite a hefty 10 a... |
H: Does a 300W Transformer use 300W when a 12W appliance is connected?
I've been wondering: if you connect a 12W device to a 300W step-up transformer, how much power is consumed? Does it use the whole 300W the entire time, regardless of what's connected, or is it an upper-bound?
I'm also keen to learn why.
AI: A basi... |
H: OpAmp: Better to actively attenuate, or drive full range into a divider?
I want to get a +-15V differential signal (60Vp-p) into an ADC that has a single 3.3V supply. When I asked a friend to proofread it, he was concerned about the noise performance of R5-R6 vs. using R1-R4 to make U2A output the desired level to... |
H: Can differential USB traces be routed relative to Power (not Ground) planes?
I would like to route my USB 2.0 (12MHz) signal on the bottom layer of a 4-layer PCB. However, the edge-coupled microstrips would then be referenced to the power plane, not the ground plane. The signals are going to the USB pins of an ST... |
H: What does this microcontroller notation mean?
Referring to this schematic, what do the little white circles with red lines mean in the pin out diagram?
AI: The circle at a pin location of a digital logic chip indicates that the signal is active low rather than active high. |
H: Two wires induced-EMF?
Is there an induced-EMF from two wires being close to each other (d = 1mm)? I'm assuming since each wire has its own magnetic field. Only in the beginning when current starts to flow and then stabilizes?
A diagram:
AI: Not only yes, but any time the current in one wire changes, it will affect... |
H: Breadboard jumper cable to PCB
I want to do some prototyping with a microcontroller on a breadboard.
The microcontroller won't fit in the breadboard holes because it is square and small, and has many pins I won't be using.
I would like to connect the pins of the microcontroller to the breadboard via the standard ju... |
H: Cleaning PCBs... using water?
I found this video where a technician with a lot of experience seems to clean his PCBs using water, and then he just puts it in the sun so it can dry. I was just amazed to see the circuit keeps working as intended, he says he keeps doing this all the time and several times, however I d... |
H: 5v DC 1.0A micro USB device hooked to an 5v DC 2.0A charger
I've bought an Power Bank rated 5v DC 1.0A in it's input but it's extremely slow to charge via USB port, which provides an maximum of 500mA as i read in internet.
I have and outlet USB phone charger from samsung rated 5v DC 2.0A in it's output and i was wo... |
H: FXOS8700CQ - Arduino core I2C doesn't work, SoftI2C does
I use the Arduino core libraries in my latest project (ATMega328P MCU)
I'm trying to talk to an FXOS8700CQ via I2C. Reading register 0x0D should return 0xC7.
The typical Arduino Wire library method,
Wire.beginTransmission(address);
Wire.write(subAddress);
Wir... |
H: Termination resistors in Ethernet in Kilo-Ohms instead of Ohms?
When working with Ethernet, whether copper or optical fiber, why are the termination resistors always in a few ohms and never in kilo-ohms?
Example: 49.9R on transmit & receive pair of PHY in copper Ethernet, 130R & 82R divider on transmit & receive pa... |
H: Did I choose the correct fuse for my USB powered circuit?
I need to drive a circuit (operational current 150mA) with a USB port. I would like to protect the port with a fuse and from
this question I concluded, that what I want is a PTC fuse. Is that the correct conclusion?
I would choose the MF-PSMF035X, but I am ... |
H: What's the correlation between spectral graphs produced using near field probes and ones produced using an antenna?
I've been looking at getting some equipment for EMC-precompliance on a budget (about £5k). I understand that I can get a spectrum analyser with some EMI options and some near-field probes (about £2k) ... |
H: MPU-6050 doubt in playgroud code Arduino.cc
I am studying the MPU-6050 and saw this article. I'm wondering in two lines of code.
http://playground.arduino.cc/Main/MPU-6050
This line from what I understand the shield guard reading the last value in this register and the source code is asking these values. That's ri... |
H: Monitoring power from 3-phase AC generator
Hello all.
The above is a circuit schematic (sorry for poor hand drawing) for monitoring power from 3-phase AC generator. The main goal of the circuit is to see how the power output varies depending on the load resistance that control the generator torque. Here are my que... |
H: Determine the speed of a solenoid
I've found this solenoid online.
In my current project I try to generate fake recoil for a lasertag marker.
Now my question is:
Can I determine the time the solenoid needs for completing one cycle?
One cycle means powering the solenoid until full length (18mm) is reached and then s... |
H: Bit error rate objectives
When designing a transmission link, are there any standardized/typical objectives for maximum bit error rate? Apart from some papers speaking about values like \$10^{-10}\$ or \$10^{-12}\$ for optical fiber I not only failed to find something comprehensive, but I found hardly anything at a... |
H: Level shifting 5V to 3.3V - can I just use a zener diode?
simulate this circuit – Schematic created using CircuitLab
My problem is the ATmega328 is running at 5V. I know I need a bidirectional level shifter. However don't really want to spend much more money on this if I can. I don't want to blow up an expensive ... |
H: Solid-state relay realized with bipolar transistor
I'm searching information about SSR realized with bipolar transistor. Basically I need something like tutorial how they are constructed, how they work, what elements they contain etc... I searched in google but I wasn't very lucky with the results. If anybody give ... |
H: How to create footprint from IC diagram when no recommended layout is given?
I'm a student trying to create a library part in Altium for an Analog Devices AD8232. Most IC datasheets give a recommended footprint to use, but the AD8232 datasheet only shows the IC itself:
I have been searching, but have been unable t... |
H: How is the voltage and current plot for a matched transmission line constant?
When the transmission line is terminated with a matched load the voltage on the line is given by V(z)=E e^(jβz).
where β is the phase constant of the line.
1)How is the voltage plot a constant for this transmission line?
2)How is e^(jβz) ... |
H: Peak-to-peak voltage of WRL-10534?
I'm experimenting with the 434 MHz RF Link transmitter (WRL-10534) from SparkFun. I'd like to determine the peak-to-peak voltage of the RF output, but I don't have access to an oscilloscope that can measure this signal. The datasheet for the transmitter says that the output power ... |
H: Wiring RS485/422 to RS232 converter to a given device pins
I'm trying to establish a full-duplex and then a half duplex communication and need to wire a device output to an RS485/422 to RS232 converter.
Here is the device output pins for full and half duplex modes:
And here is the RS485/422 to RS232 converter sc... |
H: Is it possible to create a 4-16 decoder using five 2-4 decoders without enable inputs?
So that the outputs represent a 4-input truth table.
AI: No, but you can make a 3-8 decoder out of 4 2-4 decoders.
ETA:
simulate this circuit – Schematic created using CircuitLab
So I was wrong, and it takes 5. My bad. |
H: Second-Order RLC Circuit
How do I find the second-order differential equation, in terms of \$i(t)\$?
At time \$t>0\$, the voltage source will be gone, and I will have a parallel \$RLC\$. I am having problems with finding the equation because I used nodal analysis, and now I have an equation in terms of \$v(t)\$ ins... |
H: How to transfer electrical power from stationary to rotational part.that can be used for POV display?
I have been researching how to transfer electrical power from stationary to rotational part. Some of them showed the means by using slip spring rings like in this website
http://www.luberth.com/analog.htm (under th... |
H: Where do I connect earth wire?
I'm trying to use this delay timer to control an exhaust fan. I have a 3 pin connection (with earthing wire) powering this fan and it works fine.
If I have to insert this delay timer module in between the fan and socket, what do I connect the earthing wire to ? Can I leave it connect... |
H: Suggestions on instruments to detect pachyderms
I am doing a project to detect the pachyderms in the forests when they cross the borders. Now is there is any other way other than seismic or sound waves to detect the pachyderms before they cross a border (Ruling out the camera's). I would love your valuable inputs. ... |
H: How does this non-isolated circuit create 12VDC from mains supply?
I took apart a PIR sensor, and inside it has a circuit similar to this (it uses the same chip):
I don't quite understand how this rectifies and creates 12VDC. My understanding so far is the (68 + jw0.68) is the current limiter, and the 12V zener is... |
H: Autoreset circuit for arduino - how I think it works
HI I wanted to ask the resistor and capacitor combination within the black circle, it forms an rc constant right? Am I correct in assuming when the chip is powered up, the capacitor is charged up. The capacitor is discharged when the reset line i spuled low, th... |
H: Enclosing/Casing Design for electronics (electronic eng. vs industrial designer)
I have been wondering, this since i dont have that much experience in product design, but, who is supposed to do the case design of an electronic product? the industrial engineer or the electronic engineer? i have been trying to find t... |
H: Body diodes in MOSFET symbol
As I understand, all MOSFETs have body diode. But I see some symbols have body diode shown while some not. Is there a difference in such MOSFETs?
AI: No, there is no difference. There is no "official" MOSFET symbol, just variations on a theme. The diode will always be there regardless... |
H: How to solder under already soldered parts?
I soldered several pin rows on my pcb, and thought that both sides of the pcb are already connected. Therefore I only soldered the pin rows on the bottom of the pcb. Unfortunately they weren't connected, so that I have to solder the pin rows on the upper side of the pcb, ... |
H: sine wave generator circuit with OPA604 and LM3900
I am trying to generate a sine wave signal. I am following this guide http://www.ti.com/lit/ml/sloa087/sloa087.pdf from TI. The thing is I cannot find the IC that they are using (TLV2471) and I only have OPA604 and LM3900 op-amp and the circuit doesn't work. I have... |
H: How do I structure a slow speed CAN Bus network with 400 nodes?
I'm looking into the possibility of building a CAN bus network with ~400 nodes in it. The total cabling distance is about 200m but it doesn't have to be fast; each node only needs to transmit a single packet once per minute so a data rate of 25kbits/se... |
H: 5v Electret microphone to PC mute switch pop help
I've got a PC microphone that fires off a loud pop when muted. Upon taking it apart it appears that its mute circuit is really simple and therein may lie the issue.
I've combed this board for fixes and and can't find one. There is this page on the web. The fix seem... |
H: What type of display digital watches use?
I need a "thin" seven segment display to buy. It should be in size of a digital watch. It can be both seven segment display or character display. How should I search? When I seek for 7 segment display I come across with huge things like lego parts.
AI: It's an LCD. Liquid C... |
H: Per coil vs. per phase current
I'm working on a project using this stepper motor it is rated at 1.5 A/Phase current. Initially I planed of using this driver, so I checked if it can provide enough current for the motor. The website says:
can deliver up to 2 A per coil with sufficient additional cooling
however fur... |
H: Are students required to take Linear Algebra in BS engineering programs?
Is Linear Algebra required in BS engineering programs in the states?
AI: Yes. Linear algebra is required for a BS in mechanical, civil, or electrical engineering as far as the programs I'm associated with.
Edit:
But is that common in most of... |
H: Can't modify global variables in interrupt, despite having declared them volatile
I can't seem to get my global variables (low, high) to change inside my interrupt, despite having declared them volatile. Below is my code.
I find it strange that I can modify my global variable 'change' but modifications to 'low' an... |
H: A circuit to prevent parasitic powering of FT232RL by MCU, will it work?
In a previous question I asked how to prevent the MCU TX pin (3.3V when idle) from powering an FT232RL Usb to Serial chip via the TX line:
Preventing parasitic powering of FT232RL by ATMega328P
I ended up going for a solution where I brought T... |
H: How does this wireless charger work?
I want to understand the way this circuit works. The following are diagrams of the transmitter and receiver of a wireless iPod charging circuit. I have added a link to the instructable that describes this project.
From what I have understood, the transmitter takes the DC input v... |
H: Why we need 100n cap parallel to IC power supply
I've seen this in many schematics, I also do it myself, but I don't really know why it's needed. I've also noticed that on RGB led strips, there's tiny 100nf caps, too.
Why is it needed? Also, if it's generally needed, why aren't those capacitors integrated in the IC... |
H: Arduino AnalogIn minimum current?
I've got a 12V source which I want to measure the voltage (or basically, just to check it's there) so have a voltage divider. Currently, with a 10k and 3k resistor, that brings it down to 2.77V and well within the Analog Input of an Arduino to measure, which is great. With this set... |
H: Multiplexing buttons using shift register - high impedance output
I have experience with 74HC4094, and I believe the 74HC595 is essentially the same - the datasheet says they have "tristate output", but that is only when OE is low - then all pins are tristate.
What I'd want is that high would be high, and low would... |
H: IR Led & Phototransistor pair bandwidth issue
I'm trying to sense IR wave with a phototransistor circuit. The circuit operates well under DC operations (I mean 3.3V through inputs). However, if a square wave is supplied from UART input, after 2kHz output voltage waveform become noisy DC about 200mV. What should I c... |
H: Preferred balun location? (Are differential microstrips preferrable to single-ended?)
I'm designing a PCB with a transceiver that has differential signal pins for rf. These differential signals travel to a balun, which transforms them into a single-ended signal (50-Ohm characteristic). This output goes to a on-bo... |
H: Electrical behavior of holding magnets when you pull them apart
I'm going to buy a holding electromagnet and a strike plate to hold some things, and I want to design my circuit (arduino-controlled) not to fry like bacon. I'm aware that since a holding magnet is an inductor, I should use a flyback diode and possibl... |
H: What is the maximum number of nested functions in PIC16F628A?
What is the maximum number of nested functions in PIC16F628A?
ex. [NEW CODE, should be more explanatory]
int main(){
function1();
}
void function1(){
function2();
}
void function2(){
function3();
}
void function3(){
function4();
}
// A... |
H: How to drive 30 LEDs with a smaller amount of pins?
We have 30 LEDs in a row, and we want to turn them on left to right. However there are way to many for the Arduino to have each one on a different pin.
Is there an IC that can take a binary output, and output in base 1?
AI: LEDs like that are commonly driven by sh... |
H: Filtering DC offset of a pulse train
How can I filter a DC offset of a pulse train with an RC circuit?
The signal is a pulse jumping between 3.07V and 3.53V. But I need a pulse which is jumping between 0V to 0.5V. How can I filter that 3V DC offset?
AI: The simple and obvious answer that meets your specs is:
This ... |
H: 2.8V UART to 5V MCU - how?
I'm trying to connect ZTE MG2639 to 5V AVR (or USB<->RS232). This module is using 2.8V at IO. How can I do that? Normal voltage divider?
And how to check if communication is OK in Putty? Just type "AT"? Or "AT" and press something? It's my first time playing with AT Commands.
AI: For the ... |
H: Is a switches voltage and current rating a hard limit?
I have a need for a switch that can handle 28Vdc at about ~1A.
The switches I would like to use have a rating of 24Vdc at 5A.
I would think that the limit of switch is the power, so if we take a switch at 24V and 5A, then it can handle 120W. My reasoning is tha... |
H: PWM with MOSFet- make it linear
there maybe wrong assumption in my question , so forgive me, i am here to learn .
So controlling a light(LED) with MCU that outputs PWM, into a MOSFET N-CHANNEL, as described in this little image:
so if i check the voltage in the gate, i can see clearly that it goes linearly up from ... |
H: Push button switch terminology
I'm looking for a push button switch that when you press it, it is open and then when you press it again, it is closed. I believe this is called an "alternate action" push button switch. Is this different than a "latching" push button switch?
Also, are there alternate action push ... |
H: Scaling 12V PWM signal to 0-10V
I'm trying to translate a 3.3v PWM signal through an optocoupler to the 12V side of a circuit, filter it to obtain a relatively clear DC voltage, and scale that to 0-10V for a control element.
So far, my circuit looks like this:
The square wave gen is emulating the PWM signal, the r... |
H: For a first order system, what type of response to a sine wave?
If I put a sine wave through a first order system and reconstruct it with some type of weighting (equal or not), how should the response come out?
Should the response follow the original sine wave almost perfectly, or should it not reach the peak ampli... |
H: Raw RGB from CMOS image sensor to grayscale conversion
I am trying to produce an image with OV7740 color image sensor. As far as I know, the sensor is configured by default to provide 10bit parallel RAW RGB data (due to an on-chip Bayer filter). How should this data be processed/scaled in order to obtain a grayscal... |
H: How does battery charging work
I want to charge a 7.2V-2000mAh NiMH battery. I have many solar panels and a voltage regulator but I do not know what voltage is required to charge it. I've heard people say that as long as it is any voltage higher than the battery peak voltage it is good. So I can use a 12V panel or ... |
H: Why is current going towards the voltage source in this circuit?
You can see that Is was labeled as going towards the voltage source when doing KCL at node a. Can someone tell me why? Is it not supposed to go into the node?
AI: It is just by convention.
If you draw all the currents as either going out of a node (o... |
H: Why do I see +1.5V on Din of a WS2811-based LED strip?
I'm wiring up an LED array I recently purchased (specifically, this one), and trying to identify the correct connections. I'm thrown by an unexpected voltage appearing at [what I think is] Din.
There are three connectors; +5v and ground are obvious. The third i... |
H: What do the arrows in transistor symbols point to (and from)?
Transistor symbols are often drawn with arrows pointing in one direction or the other, depending on type, like in the following symbols:
But what is the arrow actually pointing at? And from where are they pointing? Is it the same principle behind it in ... |
H: Relationship between Zener voltage and current?
What's the relationship between the current flowing through the Zener Diode? I simulated the following for various values of R, and the voltage drops quite a bit with small currents. The 1N750 has a Vz of 4.7V.
The only information related to it on the datasheet I c... |
H: How to change component values when changing tube B+ voltage
I'm starting a build a tube headphone amp from diyaudioprojects.com (the simple one: http://diyaudioprojects.com/Solid/12AU7-IRF510-LM317-Headamp/)
The projects uses a 12V supply for the tube plate voltage and states it gets decent result, although it sho... |
H: How does the plastic-tube inductor in this wireless transmitter work?
This single layer PCB (solder side shown here) is from an old fan remote:
The inductor in the plastic tube is not connected physically to any components; however, the two loops of wire surrounding it are soldered to the board. This raises some q... |
H: How to handle nested final result code in AT-command text?
I am writing a parser (a finite state machine to be more precise) for AT-commands and I don't see how to handle a particular corner case:
Here is the specifications of the modem communication:
When the DTE sends an AT-command terminated by <CR> (like ATE0<C... |
H: Name that thing... Circular 4-pin female connector
I've been asked to wire in some Octopod LED lights driven by a Pixel Drive 30 controller, but I can't work out what the connectors are between the lights. I tried to contact the manufacturer but they've been taken over and the person I dealt with wasn't able to te... |
H: Half-wave recitifer diode (0.7v) problems
I can't seem to decide which is the correct answer for this question.
An AC voltage of 5 V (peak) is applied to the circuit shown. What is the peak inverse voltage (PIV) of the diode? Silion diode (0.7v)
a) 5v
b) -4.3v
c) 0v
d) -0.7v
I know it could be either A or B.
AI: ... |
H: Transmission Line Impedance Matching Basics
From what I understand, matching a load to a transmission line means that no signal is reflected from the load, which means that at the two sides of the connection point between the load and the transmission line the impedance is the same, the load impedance. I tried to t... |
H: Notch filter transfer function
For some active filter circuit I have derived the following transfer function:
$$T(s) = \frac12\cdot{s^2+{1\over2R_1^2C_1^2}\over s^2+{1\over R_1C_1}s+{1\over2R_1^2C_1^2}}$$
I need to show that this circuit implements a notch filter, for which the transfer function is given in the fol... |
H: Calibrating buck LED driver by altering Vsens
Many switch mode buck LED drivers use a current mode scheme with a sense resistor back to a Vsens or Current Sense input on the chip. A good example is the LM3404. Here's the typical use circuit:
I am wondering can I tweak the driver, for calibration purposes, by alter... |
H: Natural discharging duration of an unpluged capacitor
Can natural discharging period of a charged capacitor be detected by a certain formula? If it is related to initial voltage and the internal parasite resistance, what are the factors affecting this quite high resistance that is measurable through a simple circui... |
H: how to decode a USB signal on a breadboard
I would like read binary data that is not formatted. Is there any DIP to decode it?
AI: USB is a high level protocol, a high speed/frequency encoded differential signal, composed of multiple formatted packets. It cannot be easily decoded, especially not on a breadboard. |
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