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-7
votes
0answers
42 views

Overvoltage on a discontinued circuit [on hold]

When is an overvoltage dangerous on DC ? On 1+ volt, 2+ volt, or 3 volts Over ??? Thanks for your help.
0
votes
1answer
59 views

Best Soil Moisture Circuit

There have been an number of circuits discussed here to detect soil moisture. Most use conductivity of the soil though there is one reference to using a galvanic cell to generate a voltage. What is ...
2
votes
4answers
281 views

Measuring a huge resistance on low voltage

I was thinking on this theoretical experiment for a while, but nothing useful came into my mind. We have a "resistor" (rather a material like plastic) with a resistance expected to be very high, say ...
0
votes
0answers
68 views

Circuit Impedance

What is the impedance of the following network? My textbook says $$Z = R_i + R + jwL + 1/jwC$$ But I can't seem to make that work.
-2
votes
0answers
40 views

DC circuit theory: Linearity theorem

I need help with the following problem: In the given circuit, $$I_{2}=100mA,I_{3}=40mA$$ when $$E_{1}=30V,E_{2}=E_{3}=0V$$ Calculate value of $$I_{1}$$ when $$E_{1}=0V, E_{2}=15V, E_{3}=60V$$ ...
0
votes
1answer
43 views

Doubt about circuits with cells having internal resistances

First take a look at the schematic diagram below simulate this circuit – Schematic created using CircuitLab And let's assume the the internal resistance of the cell is (r). So here in ...
10
votes
4answers
1k views

Why are some generic door alarm magnetic switches built using Normally Open reed switches instead of NC type?

Some generic, low-cost "door alarm" magnetic switch components are made of using "Normally Open (N/O)" type reed switches, ie, when the magnet is in proximity, the current stops flowing. If I were ...
0
votes
1answer
62 views

Led Driver/Controller for 3.3v & 5v circuit

PWM Circuit for 3.3v & 5v logic controllers @ high ampere With a 5m LED Strip (14.4W/m), a regulated 12v 10A power supply (120w) and lots of microcontrollers (Arduino Uno, Arduino Micro, ...
0
votes
1answer
81 views

Beginner: Inductors in Series and Parallel HELP

simulate this circuit – Schematic created using CircuitLab I am looking for help with what is probably a very basic question but I am new to electronics. The question I have is on a ...
0
votes
2answers
55 views

What is the bold part on monitor and some charger cables [duplicate]

On many monitor or chargers, there is a bold part: First of all, what is it called? Then, what does it do? Does a cable without this part have any advantages as we see nowadays many chargers ...
0
votes
2answers
23 views

0-5V supply to control brightness of BWTek spectroscopy light source

I recently installed a BWTek BPS101 tungsten halogen light source and would like to take advantage of the builtin support for manipulating the operating current (changing the brightness) via an ...
1
vote
1answer
21 views

thevenin dependent source finding Rth

The answer is 16, but can anyone please explain how? note m is u I confused because, I dont know how to solve for Vx ? I know that once I find Vth and then resolve the circuit closed and finding ...
1
vote
2answers
70 views

Help drawing a circuit diagram from a logic diagram

I have managed to work out a logic circuit with 3 inputs and 5 outputs, but I have no idea how to translate this into a circuit. I am guessing it will require IC's or many transistors. The inputs ...
1
vote
2answers
36 views

PCB coil electromagnet driver

Based on external sensor inputs, I want to vertically pulldown & release (in a controlled manner) a 7mm neodymium magnet enclosed inside a circular elastic diaphragm. I want to keep the size as ...
0
votes
0answers
36 views

How do I create GPIO outputs from circuit to connect to Arduino Micro

how do i design the GPIO outputs so i can connect it to two pins on my Arduino and get the readings. ie. if green didoe is on GPIO 1 = High, other wise Low if red diode is on GPIO 2 = High, ...
0
votes
1answer
38 views

Using Metal thumb tacks to trigger events

I am new and curious to electronics, The below video shows a circuit bent keyboard using a keyboard made of thumb tacks to control the note input. I would love to know how this was done. The video: ...
-6
votes
1answer
54 views

Why current does not flow in few branches of these circuits?

This is the first circuit, why there is no current in upper branch. If you want a video which show the direction of the current you can check this (http://srecorder.com/s/1ok4 (this link will ...
-3
votes
0answers
36 views

how can i design a simple circuit that can be use to charge a DC(12v) using AC of 220-240V [closed]

pls I have an SLA battery of 12V I want to connect an AC of 220-240v to charge the battery. what are the processes?
0
votes
1answer
25 views

Relationship between capacitance and capacitor voltage rating?

I recently went to buy a capacitor of 10 microfarad and I was told by the shop that 10microfarad 67 volt is available. The confusion for me is that will I be able to charge the full 10microfarad only ...
0
votes
1answer
38 views

Determining whether a circuit element is shorted or not

Take a look at the image below, Why is that bottom voltage source is shorted? (http://everycircuit.com/app/) give me the response as voltage source is shorted, why is that? As far as I know, If an ...
0
votes
5answers
120 views

Doubt about potential difference through a resistor?

First of all let me give you the schematic diagram of the circuit, Here, how to find the current passing through 150 ohm resistor? These are the things I have tried, Since I want to find the ...
-1
votes
1answer
88 views

How to find voltage across X and Y

This is the schematic diagram of the circuit This is a homework question , which belongs to mcq type It is about finding voltage across X and Y? Is there voltage between x and y ? I wonder if ...
0
votes
4answers
103 views

How to find potential difference at A

As shown below the schematic diagram is given.Point B is grounded. I did take the potential at A is 2V since it is on the same node where the 2V batteries are located , am I correct? . I want to ...
0
votes
3answers
71 views

Increasing Frequency of a Signal

I was wondering if it would be possible to increase the frequency of a signal by a fixed amount. Basically, I have a negative wire soldered to a speaker and a positive wire that very quickly ...
0
votes
1answer
102 views

Why PNP transistor might be opened even though (almost) nothing is connected to the base?

I have a simple printed circuit board with simple circuit on it. Very beginner. No SMD. As a part of this circuit I have transistor BC557. If I don't solder the base pin of this transistor and test ...
0
votes
1answer
31 views

LT SPICE Simulation Error OPA1664 and AD8067

I simulated circuit which consist of a trans impedance amplifier ,some multistage amplifiers and filters.In my first circuit TIA used is AD8067 and for other parts I used TL074 op amp from TI.This ...
0
votes
1answer
19 views

BCD Switch Resistor Network for Proportional Voltage Output

My goal is to wire a BCD switch in a 5 volt system and get a voltage proportional to the 0-9 on the switch. My first thought was BCD -> R/2R network. That does not work because the R/2R network ...
-1
votes
0answers
32 views

How do timing networks work? [migrated]

I am curious on how timer networks are used in Corridor Lighting systems and what components are used?
0
votes
0answers
11 views

How to move multiple symbols in Allegro?

Can I select multiple symbols in Allegro and drag them? They are all on the top layer and I just need to move them to make space for another component.
0
votes
1answer
51 views

DC Motor circuit polarised 2 directions switches

I'm totally new to electronicS and do not understand a lot and I've read other posts but people seem to be asking different things to me so apologies in advance if this has been covered but I've typed ...
-2
votes
1answer
35 views

controllable and accurate static charge generator

ive been doing some research on methods to generated static charge. ive come across 3 main methods: wimshurst generator, van der graaf (and Negative Ion Generator). wimshurst and van der graf seem ...
0
votes
1answer
55 views

What is the variation of ammeter reading with PQ

Honestly, this is a homework question. A screenshot of it is given below: Okay these are the things I have done in order to take the answer. First I calculate the equivalent resistance which ...
0
votes
2answers
50 views

DC Motor control setup and circuit design. 1.5Hp continuous duty @ 95v dc

I have a DC treadmill motor rated at 1.5Hp @ 95v Continuous duty, though the motor label also states that it is a 2.65HP motor and that the amperage is 21.4. I would like to be able to SAFELY run and ...
0
votes
0answers
8 views

Falstad circuit simulator not displaying text

I've been trying to run the falstad circuit simulator on firefox on elementary os luna, however I can't seem to view any of the texts, such as for selecting components and such. I can right-click to ...
0
votes
2answers
84 views

Finding equivalent resistance?

The image shown right below is a schematic diagram of the circuit. There we need to find the equivalent resistance through X and Y. I reduce the inner most resistors , because I figure out that ...
-3
votes
1answer
49 views

What is the potential difference between A and B?

Here is a schematic digram of the circuit. And I take a equivalent circuit for the above circuit as shown below. These are the things that I can figure about this circuit. Potential ...
0
votes
4answers
117 views

Understading negative feedback [duplicate]

There is a question here about something similar, but it's asking about the internals of an op-amp. I'm having trouble understanding the function and use despite several hours of YouTube tutorials. ...
0
votes
6answers
156 views

A doubt on potential difference

This is a schematic diagram of the circuit. Is it possible to take the voltage difference between AB as E? I have learned that the potential difference in parallel circuits are the same, ...
0
votes
1answer
68 views

Changing potentiometer from a gaming steering wheel

I have Logitech's vibration feedback wheel which has a rotation of 270 degrees. I am considering changing its potentiometer so it can rotate more (900 degrees or 1000 degrees maybe). What ...
0
votes
1answer
111 views

How to find the direction of current of the circuit?

Okay this is the circuit The magnet given is moved up and down continuously at a high rate through the coil and generates a peak voltage of 4V. I eagerly use the right hand rule in order to find ...
0
votes
1answer
65 views

How to determine potential difference of a point on a circuit relative to another point?

I know this is a simple question for many of you. But still I am a beginner in this field.So I hope it is vital to know about this. Okay let's assume we have a circuit like below. In this circuit ...
0
votes
1answer
44 views

Tracking a circuit path across a crack?

I am new to the world of electronic repair. I have connected several wires to this board and have been successful in getting the paths across the crack to connect. Is there an easy way to trace out ...
0
votes
0answers
15 views

full inverter circuit with a buzzer circuit [duplicate]

I analysis the Lm324 circuit and i understand how it work without the C9 and C11 , but I want to know what the function of these tow capacitors.
0
votes
1answer
48 views

How does this timed fan controller work?

My bathroom fan controller recently started misbehaving, so I pulled its PCB out. This is what I found. simulate this circuit – Schematic created using CircuitLab LIVE/NETURAL are the ...
0
votes
1answer
52 views

Triangle Wave Generation

What would be the best way to generate a triangle wave that can operate at 250kHz @ 4V peak-to-peak? I have tried the following circuit: However, the best I could obtain was a 4mV peak to peak ...
0
votes
0answers
46 views

Adapt electric motor to manual seeder

I am limited on my electronics knowledge, but I want to adapt an electric motor to a manual corn and bean seeder. Why? Because it is very hard agriculture work. It is needed two people, one in the ...
0
votes
2answers
58 views

Measuring the dampening sinusoidal wave of a simple LC Tank circuit?

I've been trying to do the simplest of things...measure the decaying sinusoidal wave of a LC Tank circuit on a breadboard. I've created an "inductor" out of a coil of copper wire I wrapped around a ...
0
votes
0answers
96 views

Very Basic Schematic Wiring

So I've attempted to wire the schematic and want to make sure I'm doing this right, and have some questions answered. I'm using a potentiometer as a stand-in for a BJT since it also has three leads ...
1
vote
1answer
36 views

adding parallel Impedance 1

A homework problem tells me to find the equivalent impedance, so I added the series and parallel impedances just like I would a resistor; however, I don't understand how does one go from ...
0
votes
2answers
79 views

Circuit analysis and general study tips [closed]

The more work I do in the field of EE, the more I realizing that my general circuit analysis skills are usually the root of my confusion and could use improvement. Even after putting on my ...