# All Questions

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### Water pump with opto-isolator MOC3063M and triac BT137

I have designed a circuit for water pump. Please correct me if I am wrong with schematics. The idea is to to switch on/off AC motor pump with 230V and 7.5A, when water is detected. I have used ...
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### Convert a device that is powered by a 12V 2 amp ac-to-dc SMPS to a battery powered device

I have looked up my requirements in all possible sources (Google, StackExchange, DiY boards, etc.) but I have not been able to find a clear answer to my problem. What I have is a device that needs ...
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### Normally closed SSR won't work with grounding out a magneto's primary to ground

I've been trying to find a device that will ground out a magneto's coil (primary kill wire) in a normally closed state without using a traditional relay. I began to search for normally closed solid ...
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### Arduino (ATmega328) In circuit programming?

I am designing a circuit/software for some guy.. I am using a Atmega328 surface mounted micro in the design and am just supplying the schematic and code. He is going to build it (make a PCB) and use ...
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### What is the purpose of a PCB with no copper tracks, but only unconnected copper rings?

I am new to electronics so sorry if this is obvious to you all. I have a PCB which has the perfect size for a project of mine, so I would like to use it if possible. However, the copper plating on the ...
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### Non ideal op-amp equivalent circuit output voltage

I am creating this question to ask you about a "strange" behavior I am observing in Matlab about an op-amp circuit. I am reading "Fundamentals of Electric Circuits" the 5th edition, and in the chapter ...
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I am using the MSP430 Launchpad and I have a question regarding photoresistors. The thing is that when you connect a LED with a pin in Launchpad, which you have configured, as output I read that you ...
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### Find the resistor's value

I have bought some resistors and I am trying to find their value. The thing is that in class they taught us that you use the gold strip to find which is the right side at first and then you check the ...
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### Can I split a USB cable's male end, add a second male plug, and draw 10V from 2 ports instead of 5V from one port for a single device?

Say I have a device that accepts 10V @ 2A, and I have a wall-wart with two USB plugs that both output 5V @ 1A. Can I add a second male connector, connect both connectors to the wall-wart's two ports, ...
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### Will crosstalk be induced if signal running in parrallel to power trace?

I haven't come across any mentions of signals running in parallel with power traces. Everyt mention thus far has been two signals to each other. If I have a low amplitude signal (sinusoid < ...
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### VHDL code to convert 5 bit vector to integer [on hold]

I am stuck in the following problem- I need to write a VHDL function that converts 5 bit vector to integer where integer value of binary number a4a3a2a1a0 can be computed as (((0 + a4)* + a3)* + a2 ...
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### Photo transistor in parallel

I'm a beginner and trying to figure out how this circuit works (its a simple circuit that glows an LED when dark) : https://www.youtube.com/watch?v=eIGWWKThprI&list=UUhtY6O8Ahw2cz05PS2GhUbg#t=65 ...
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### How to learn circuit design if I already know some circuit theory [on hold]

I'm a recently graduated electrical engineer, but my curriculum never focused on electronics, besides the standard introductory level courses. I specialized in telecommunications and I mostly work on ...
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### Delay of a Binary multiplier [on hold]

I am trying to solve a problem about binary multiplier, this is the question, The maximum delay of a binary multiplier is 450ns, when based with VDD=3.3V The threshold of the transistors is 0.4v, the ...
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### fast microcontroller with accurate timing [on hold]

I can meet the specifications of a project that I am working on with a 32-bit 16Mhz microcontroller that uses an external crystal oscillator with a stability of 100ppm. Are there faster ...
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### Manually Drill Vias into PCB

As shown in the photo below, the PCB design was sent for fabrication without the drill data. Is it still possible to drill the via holes so we can save the PCBs? This is a 2 layer board, most of the ...
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### Safety advice for best EMF detector and body shielding for UHF RFID reader

I've got a UHF RFID detector (860 to 960 MHz). I'm just getting into configuring the power output but I think I've been testing it at about 20dBM, I might want up to 30dBM. I'm concerned about my ...
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### RC filter transfer function and gain

For a standard basic RC Filter, the transfer function is as follows: $${ V_{out} \over V_{in} } = H(j\omega) = { 1 \over 1 + j\omega RC }$$ However, when simulating the circuit, I find the output ...
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### What is the minimum bandwidth required for a digital communication system using 32-QAM modulation?

If the bit rate of the digital communication system is 'R' Kbps & the modulation used is 32-QAM, what is the minimum bandwidth required for ISI free transmission? My understanding & analysis ...
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### transient analysis in aim spice

How do I carry out the transient analysis of series RLC circuit using AIM Spice? I can't figure out what values should be given for step size and final time. Also, I was seeing some tutorials and ...
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### Low power Cmos Op-Amps

I recently designed a 2 stage micro-power op-amp in Cadence Virtuoso with an open-loop gain of 36dB. I checked the voltage swing in open-loop and got a full swing from 350mV to -350mv for a dual power ...
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### Parallel MAC unit based on modified booth algorithm

The below diagram is the parallel MAC structure. In parallel MAC both partial product addition and accumulation take place at same time. The partial product summation + accumulation unit of above ...
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### Eagle: Remove some text of a compoment label

I routed a small board that will get connected to a BeagleBone Black using two 8x2 pin header connectors. As you can see on the picture there's two labels that are drawn out of the board layout so ...
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### Use Arduino for switch a 12v powered remote control

I've a remote control powered by a 12v battery. I need to switch a button using arduino, can I use directly the digital pin without any relay or transistor? Thanks in advance
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I am building a two way radio system using the citizen's band in India. The transmitter is using a 555 timer IC clocked at a frequency between 26.957-27.383MHz to transmit AM waves. Can you please ...
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### Does the output of JK Flip Flop toggle continously?

As given in most of the texts and online resources, the JK flip-flop requires a clock signal with an edge detector circuit so that the flip flop will be sensitive to the inputs only when the clock ...
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### GOTO a specific address in HI-TECH C Compiler PIC18F

I'm trying to jump to a specific address in HI-TECH compiler and the address is given dynamically. I tried using asm() function but it looks like the argument must ...
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### Amperage for Sony SNC-VB630 Camera [on hold]

I am trying to choose a right DC adapter for SNC-VB630 CCTV Camera but the only specs I could find in the official documentation was 'INPUT 12V DC'. Nothing about amperage. I have a 12V dc adapter ...
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### Buffer circuit explanation

I just saw this question and was wondering how this circuit actually works, since I couldn't really figure it out, I though about asking it. This is the circuit I am talking about: Lets label ...
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### libmodbus trouble with reading from slave

I have the following code for connection to a temperature sensor as my slave using the libmodbus library in C, ...
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### Can I build a high-frequency SMPS choke out of an arbitrary coil of wire?

Suppose I want to build a boost converter that runs at 100 kHz, with an input voltage of 600VDC and an input current of 100 amps. (This is hypothetical, I know the semiconductors involved would be ...
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### Using explicit registers in RTL designs

Is it a good practice to use explicit register IPs in RTL designs? For instance, having separate IPs for each type of register and instantiating them in the design instead of coding them on-the-fly. ...
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### Embedded software C/C++ for FPGA programming [on hold]

How hard is it for someone with a lot of embedded software/system experience to transition to FPGA programming for ASIC chips? Fundamentally it is about the logic, am wondering about the ramp up time. ...
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### looking for a smart way to compare DCDC Converter IC

I'm looking for a quick and easy way to compare DCDC boost Converter IC, to all or most manufacturers. Does anyone know tools, sheets or charts? Thanks!
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### SMPS Inductor oversized vs properly sized

I am working on an SMPS for boosting an input voltage to drive a single string of LED's. The input voltage range is from 18 to 32 volts. The output voltage needs to be about 60V and the drive current ...
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### LDO Regulator Overshoot

I'm using an LP38691 3.3V fixed regulator which is overshooting. This wasn't an issue for years, but now a component is being replaced and the current on the 3.3V rail has gone up from 300mA to 500mA. ...
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### Tactile pressure sensor and drift. Reading the datasheet

I am looking at the specs of tactile pressure sensor and I can't understand what this means: "Drift: <3.3% per logarithmic time scale" How should I understand this? Does this sensor drifts a lot ...
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### Relationship of voltage and time in dielectric breakdown/withstand tests

Is there a simple relationship between voltage and time in dielectric breakdown/withstand tests of cables, connectors and other electromechanical parts such as piezo elements? For example, if in a ...
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### Convert transformer resistance data from Watts to Ohm

Short version: How can I convert transformer resistance values from Watts to Ohms? Long version: In PSS/E, transformer resistance can be entered as either per unit values (system base or transformer ...
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### I want to build the cheapest AR drone with camera and wireless/radio connectivity. Suggestions? [on hold]

I'm currently studying embedded systems and I would like to get more experience, especially in flying drones (I like them). I searched around and found already made solutions at high prices, which ...
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### Current overlap in Inductive Smoothing?

I have the following circuit implemented in the lab : And the output was : Can anyone explain why the current overlaps here ? I can't make sense of this.
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### Software for drawing circuit diagrams [duplicate]

I have a simple project with some LEDs, LCDs and a few shift registers connected to an arduino uno. I want to be able to draw the wiring/circuit diagram a bit more professionally than what I can do in ...
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### Diodes in series

simulate this circuit – Schematic created using CircuitLab The diodes are both made of Silicon. What will be the voltage across D1?. Edit: I voted for 0V only. But this is the ...
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### When to use process statement in VHDL

I was wondering when I am suppossed to use process statement in VHDL. I saw some examples in books but all of them could also be written within concurrent structure? I use VHDL to program FPGA.
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### Are there any high energy density (i.e. zinc-air or lithium-manganese dioxide) batteries without high internal resistance?

For my wild life camera, I want a small cell that can provide 0.5W for 8 hours or more. It doesn't seems rechargeable lithium ion batteries have that energy density. I don't mind if the cell is ...
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### Zener diodes in series

Hello, In this problem, i am not able to understand how I2 is getting replaced by I01. More over, will these zener diodes become ON as the applied voltage is less than Vz? Thanks in advance.
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### how to write verilog code related to Asyncronous Transfer mode QOS implementation [on hold]

if possible explain me about the code or else if you have any code related to this project please send me to my mail ID.... My project title is Asyncronous Transfer mode Quality of service ...
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### impedance matching to mechanical sensors?

i am working with 40 sensors in that almost all sensors are mechanical but some potentiometers are converting those mechanic displacement into voltage but resistance of voltage source is changing ...