# Questions tagged [circuit-design]

For questions about the design of circuits. This may cover everything from processing steps to models to high level circuit design issues.

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### Dipole antenna calculations

I need a clarification about how to calculate the length of a dipole antenna. For a 1/2 wave-dipole which of the formula is correct? (140/λ) Or (300*10^6/λ)/2 Can a 1/2 wave-dipole dipole work when ...
48 views

### Is there a way to short a low voltage circuit remotely without physically touching it?

I'm looking for a way to short a low voltage circuit remotely without having to physically make contact with it. A preinstalled discharge or shorting circuit can't exist in this case. Just any random ...
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1 vote
136 views

### Converting time constant to bandwidth of 1st order system

When the system is first order: $1/(1+s\tau)$ Why is the bandwidth: $f_{-3db}=1/(2\pi \tau)$? Where did the $2\pi$ come from? Why isn't it simply $1/\tau$? The unit of $2\pi$ is related to radian. But ...
• 13
32 views

### CMOS AC-to-DC Converter Design

I am trying to analytically model the power conversion efficiency of an AC-to-DC power converter circuit (see Figure 1). In this design, the drain-source voltage of each MOS device can be expressed as ...
56 views

### Strange problem with Impedance?

I've encountered a strange problem with a 12V key-fob device. We use a device to remote control a relay via a key-fob transmitter. It's installed in a plastic box that is mounted at an operator ...
36 views

### How do I draw a circuit for a conducting loop inside a solenoid?

To solve a homework problem, I need to redraw the following diagram in circuit form. The large blue circle represents the solenoid. Inside the solenoid, the two gray semicircles represent a wire loop,...
1 vote
50 views

### What should be the clearance and creepage for the line to line 440 Vac and line to neutral 240 Vac of the three-phase system on PCB?

Also is there any link to calculate this as per the UL and other industrial standards
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59 views

### How to build a 4-bit full adder that shows result on 2 7-segment LEDs, without using Arduino?

I'm required to create a 4-bit full adder (ALU actually), that displays result on 2 7-segment LEDs with both are common cathode, using only 74HC283, CD4511 and some other logic gates. I'm confused on ...
88 views

### Why does a metastable state eventually resolve to a stable state?

I was studying with a book named "Digital design and computer architecture". When I read the part of metastability, it stated this without any additional explanation.. Why does a metastable ...
• 101
236 views

### How to make motor spin the other way

Let’s say I want two motors in parallel in a circuit (so they get the same Voltage), and wanted one motor to spin anti-clockwise and the other clockwise- is it possible? I thought by flipping one of ...
• 13
1 vote
367 views

### Precisely control voltage output

I think the component name is a rheostat- is that what allows you to control the voltage output please? I want to control it in steps close enough to 0.1 ish volts? So I would like to attach a knob ...
• 13
58 views

### How to Supply two different DC voltages using High Current

I'm trying to function a 12V stepper motor(>2.5A) and five 6V servos(>3A). Are there any reliable circuits that can output both these voltages and a high output current since there will be some ...
• 33
161 views

What would happen in real life if you made a paradoxical circuit (a circuit whose output is on iff its output is off). Something like this: Would the discrete model break down and the output end up ...
1 vote
181 views

### Electrical potential and grounding in a circuity, why it works?

I thought I understood the ground concept but now I'm a lot confused. From: Pg.67 Practical Electronics for Inventors - Scherz Paul As it's explained in the book, the first circuity is the one that's ...
19 views

### Building drone transceiver module with 2 recievers onboard to switch gates ON/OFF to turn motors On/Off

I'm looking for any resource that can help me build a radio (no infrared) controlled circuit with two receivers onboard a drone. The purpose of this circuit is for research and education. Whenever ...
1 vote
97 views

### What are the charge/power connector of restaurant order pagers / buzzers called?

They look like snap buttons and used for stacking pagers for charging. Closest things I can find are socket screws and cap nuts.
43 views

### Explanation for photovoltaic circuit

My background is in Environmental Science, although I have recently been taught in the basics for energy engineering especially for solar panels. I'm currently using PVsyst to build solar panels on a ...
• 105
532 views

### Arduino DAC to Speaker

I'm working with an Arduino Due's two DAC pins. I want to output to a single 4W 5.7Ohm speaker to test my code, with the intent of eventually outputting to a set of speakers (woofer, mid-range, and ...
1 vote
517 views

### Building oscillating magnetic field circuit

I wanted to create an oscillating magnetic field using an electromagnet which is rated for 12V continuous duty. I was thinking that I need an arduino to control the electromagnetic circuit by using a ...
• 153
428 views

### What signals are expected on the connectors for this 12V Volkswagen Scirroco wiper motor circuit

EDIT: added a picture of a very similar unit. I picked up a used VW rear? wiper motor that I want to use for a simple motion experiment. Having no idea how to power the thing I popped open the case ...
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1 vote
114 views

### Designing RLC circuits at specific frequencies for teaching use

I need help designing simple circuits that resonate around specific frequencies. Basically I am looking for recommendations as to what size capacitor, inductor, and resistors I should get. Sorry if ...
• 13
812 views

### How can I calculate overcurrent from over voltage for the AP9101C IC

I designed a battery charging, protection, and boost circuit for a project I am working on. However, I made a complete noob mistake and forgot to find the overcurrent value for the battery protection ...
241 views

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1 vote
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### How do they get more signals simultaneously inside a node of a neural network? [closed]

Why the circuit does not freeze/lock when the signals SUM ? But the electrical signals are SUM together in what sense? This question is about neural network circuits because I don't understand what ...
• 11
3k views

### Square wave transfer function?

I made a mathematical model (transfer function) of a rlc circuit. I simulated it in matlab simulink with step input and square wave input and observed the result. I can also calculate this system with ...
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61 views

### Is there any hardware to use in GPR applications? [closed]

I want to make a radar system which needs to send EM wave and receive the reflected wave from the ground. I am looking for a ready to use RF signal processing hardware but can't be sure which is ...
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1 vote
3k views

### No Voltage appearing on Pspice

I am trying to compelte this question, however when i run the simulation there is no voltage atall on the output votlage, and cahnging the capacitor value as requested in the question does not chane ...
185 views

I am having trouble finding a 3.4 µH through hole inductor that is in stock right now. I was wondering if I can just place 2 inductors that add up to 3.4 µH in series to solve this problem. I am not ...
1 vote
113 views

### Circuit that multiples two numbers together?

Design a combinational circuit that multiplies two numbers together, and outputs the result. The biggest product will be 3 * 3 = 9. Four bits to represent the product. ...
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