# 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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73 views

### Voltage controlled switch?

So I am in the process of working on a rather strange and specific project. I am looking to capture as much energy as possible from a small steam turbine using a DC motor and then use that to power ...
47 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 ...
1 vote
95 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 ...
28 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 ...
55 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 ...
1 vote
246 views

### Designing a loaded voltage divider?

I was wondering how to design this circuit in depth, since I have no idea what to do.
34 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,...
798 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 ...
1 vote
48 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
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 ...
80 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 ...
216 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 ...
1 vote
316 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 ...
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 ...
151 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
174 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 ...
1k views

### What controls the gain in a BJT amplifier, and why does this circuit have a gain of unity?

In the case of the first circuit, The ratio between the input voltage Vin and the voltage at the collector and the ratio between the input voltage Vin and the voltage at the emitter are supposed to be ...
18 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
96 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.
42 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 ...
516 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
483 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 ...
409 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 ...
1 vote
570 views

### PC Controllable DC Power supply (0-30V)

I have a Proportional solenoid valve that uses a 0-30VDC for control (opening the orifice) I only have capability to provide 0-5V or 0-10V. I need to control the valve using my PC. Is there any DC ...
1 vote
675 views

### I am trying to create an op amp based negative voltage regulator

I am trying to find simulate an op amp based linear regulator negative voltage regulator circuit. I have done the circuit for positive voltages, but does not know how to do it for negative voltage. ...
1 vote