Tagged Questions

Voltage, otherwise known as electrical potential difference (denoted ∆V and measured in volts) is the difference in electric potential between two points (adapted from Wikipedia). Voltage can be constant (DC) or varying (AC).

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17 views

1A Voltage Regulator - Maximum or output?

I want to design a circuit that has 12V1A output from a battery. I am using a 12V voltage regulator Do I want a 12V 3A Regulator or 12V 1A regulator? If a 12V 1A voltage regulator gives me a better ...
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1answer
46 views

Is accelerometer taking as much power (current) as it needs? [on hold]

I want to connect accelerometer to an oscilloscope. I have 3x AA rechargable batteries (2550mAh). I was told that e.g. microcontroller knows how much amps should it take and it wont burn if I ...
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0answers
20 views

Datasheet for Keyes IR Transmitter (KY-005) wanted

Can someone help me find the datasheet for the Keyes IR Transmitter (KY-005)? I know how the pins work, I just need to figure out its voltage drop and how much current should go through it. Thanks! ...
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1answer
27 views

Finding Vo with superposition method

simulate this circuit – Schematic created using CircuitLab
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1answer
57 views

Total voltage towards load?

What would be the resulting voltage in a DC circuit like this: Where there are three voltage sources, it seems that two are in parallel(20V,5V) opposing 15V source So would the total voltage be ...
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0answers
61 views

Relay voltage drop, a solution?

I simulated an H bridge with 2 relays and one motor in PROTEUS. Everything is 12 V and DC, I set relay coil resistance at 80 ohm ( I am replicating this : ...
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1answer
43 views

Resistance and voltage drop conclusion [on hold]

Is it true that the higher the resistance the higher voltage would drop?
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1answer
48 views

Voltage divider VS Voltage translator [duplicate]

I am building a PCB with some ICs. To sum up, I have a global 3.6V supply and I need to have an 1.8V reference for some IOs. I know the right way to do it is to use a voltage translator circuit ...
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0answers
44 views

PWM from 1v to 5V convert to 12V

guys thanks for time and help... i need to convert the signal of pwm output the pwm signal cand delivery from 1v to 5v i need to read this signal and boost to 12V for on/off relay where i can find ...
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2answers
53 views

opamp as inverting amplifier

I have this doubt which is freaking me out. First of all I am all confused between open and closed and ideal characteristics of the OPAMP. My main doubt is this: Considering the OPAMP as Inverting ...
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1answer
92 views

Why there are live and neutral wires attached to house's wall sockets

If AC voltage is alternative, why there are two (Suppose there is no earth wire) wires attached to the wall socket: live or hot, neutral wires? And I think that in small home generators there is no ...
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2answers
65 views

voltage drop when using voltmeter

it's a theoretical question. is there any voltage drop when measuring a 12v battery with a multimeter(voltmeter mode)? so if we get 12 Volts reading near the battery, does this changes if we extends ...
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3answers
81 views

Diodes block voltage?

I understand the basics of a diode, a diode allows current to flow in only one direction, but how? By blocking any opposing voltages source so that no current can flow in opposition? And of course, a ...
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3answers
87 views

Voltage standards? Like 3.3V, 5V etc [duplicate]

What exactly are the main voltage standards called for all the common voltages we see? 3.3V, 5V and 12V are some of the most common DC voltages but what are they known as exactly and what's with their ...
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1answer
39 views

Design of 5 - 15 MHz Voltage Preamplifier

I'm trying to design a power amplifier for the HF band to drive an inductive charger. The stage I'm working on now is a voltage preamplifier which needs to be able to amplify 1 Vpp to 10 Vpp. The ...
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0answers
54 views

Best way to take 110V down to use with 12V motor

I'm building a lamp that continuously spins, and wish to use a 110V wall outlet to simultaneously power the lightbulb and a small motor. What is the most efficient way to do this? I'm new to ...
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0answers
89 views

Voltage drop across outputs in my 4 iPad connector

I designed a circuit to plug several iPads at the same time. To feed from the circuit from my connector I'm using a variable switching power supply rated at max 12V 10A, I adjusted the output to 5.2V ...
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2answers
58 views

How to run a 6v 4amp motor at slower speeds for long periods of time (2 hrs)?

I am trying to get a project done for Halloween. I am running a 6V 4A motor (from a powerwheels) but need it to run slower. I tried using an adjustable charger and ran it at 3V to slow down the ...
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1answer
96 views

What happens if I supply 18V to a 12V lighted switch?

I am fairly inexperienced with electrical engineering and usually just wing small things I.E. a current project. Basically I have a project box, with a 12v arming switch with a red light in it. ...
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1answer
65 views

What is cut-in voltage of a transistor?

Some literature talk about cut-in voltage but couldn't find a clear explanation.
1
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1answer
105 views

Specification Requirements for a TVS Diode

I want to add a transient-voltage-suppression (TVS) diode to my design, but am getting confused about the specifics around Maximum Clamping Voltage, Maximum Peak Pulse Current and Minimum Breakdown ...
0
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1answer
65 views

Measuring Current in 12V DC Fan

I am trying to measure the current of a DC computer cooling fan (Intel E18764-001) at various volts. Its rated specs are: 12V 0.20A. Check it out here. So I am suspecting that this is telling me: ...
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0answers
34 views

Switch capacitor analysis without initial condition

The figure below is described as: C1 and C2 are the pumping capacitors but at given time and conditions of clocks (VCk and VCk'), C1 is being charged while C2 pumps its stored charge to CL (load ...
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3answers
37 views

Subtracting from lipo cell voltage!

I just got a 3s Lipo battery. Lipo battery has a 4 pin connector to plug it into charger or voltage checker. But I don't want to buy a lipo voltage checker, I want to make it. But I have a problem. ...
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2answers
145 views

Voltage not dropping in circuit

This schematic shows the circuit that I'm trying to build. At the moment I'm not using V2, as I'm having a problem with V1. From my understanding the diode should drop the voltage by about 0.7V, and ...
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2answers
47 views

Can I use a 250 VAC socket for 120V power?

I live in canada and I'm trying to build some DIY audio gear. I'm using a toroid http://www.digikey.com/product-detail/en/VPT30-830/237-1326-ND/2090064 (115, 2x15v) And this socket to go with it ...
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2answers
116 views

Is it possible to amplify near zero signals?

Is there an amplifier has an ability to amplify any signal down to -500 dBm? If there is not, can it be possible? If it is not possible, what is the weakest ever signal that can be amplified?
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1answer
72 views

OP amp output not changing ( schematics )

This is a image of most of part of my circuit (555 timer IC is cut from right side)... using the pot (RV1) , I change the non inverting input voltages of the op amps. when non inverting exceeds ...
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2answers
64 views

Capacitance - Voltage characteristic diagram in a Schottky diode

I 've searched the web for that diagram with no satisfactory result. Does a schottky diode has capacitance or not because of very tiny depletion (almost none) zone ?
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0answers
41 views

Max peak to peak swing across ES without any clipping distortion?

This is an exam problem in which my instructor gave the answers but no work. Any one has an idea of how to solve it;FOM(figure of merit)= 25/125, RL=15 ohms, Rx=250 ohms, r1,r2,vee,vcc, are not given. ...
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1answer
71 views

110v 220v do it work? [closed]

i bought hookah heater from amazon. this product link is ...
0
votes
3answers
98 views

Resistors in series or one after?

I want to use a Voltage divider and i need to divide 5v to ~3.3 so I ordered 10K resistors on eBay, but the voltage divider needs a 20K and a 10K, can i use 2 10K's parralel as a 20K
1
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1answer
74 views

About a solar cell phone charger

I recently made a solar charger. The output energy of solar cell is 2 Watts. The voltage is around 20 volts. I used 7805 IC voltage regulator so i could get around 5V. I used a female USB and ...
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6answers
144 views

How to calculate Vo in this circuit?

In this circuit: The diode is an ideal diode The diode is on since V(anode) > V(cathode) and then we replace it by a short circuit. Now, how to calculate Vo when two sources are existed? I = (10 ...
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1answer
134 views

Breadboard circuit not working as intended

I'm doing a segment of my complete circuit for my school project. But somehow it doesn't seem to work , I've double checked the connections multiple times and I can't seem to find an error. ...
0
votes
1answer
49 views

Grid voltage swell and sag, what happens to harmonics?

I know that when a load draws too much power the voltage of the grid at the fundamental frequency begins to sag. Though my understanding is that loads can't use the power generated by harmonics, so ...
0
votes
1answer
104 views

Jump start car from lithium ion laptop battery

Building the actual circuits is beyond me at this point, but I'm wondering if it's technically possible to jump start a car from the power contained in a large lithium-ion laptop battery. For ...
1
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2answers
79 views

Output voltage of unity-gain buffer varying with current?

I'm working on a VLC+IR transmitter that runs from batteries. I decided to use an LM317 so that the discharging battery wouldn't really affect the current through the LEDs. (Disclaimer: I've never ...
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3answers
85 views

Very wide range high voltage measurement with optical isolation

I have a voltage source I'd like to measure, it is from 0V to 1kV, any value in that range. The accuracy isn't that important, but measuring with an accuracy with 1-5% would be perfect. This has to be ...
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4answers
171 views

Why do we need 3 phase power supply?

Why do we need 3 phase? For the reason that voltage will never be zero in 3 phase? OR we need high voltage?
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0answers
33 views

Problem on finding the charge transferred and voltage between capacitors

The goal here is to solve for the voltages between capacitors (i.e. voltage in C1, Cx, C2 and CL). I am aware that during this time the Voltage in C1 is equal to the node voltage at node A because it ...
0
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3answers
103 views

When is the AA battery voltage drop?

I have a device which is running on two AA Duracell batteries. The batteries (brand new) together is producing 3.2 volts (1.62 volts individually), which is estimated to run for at least 2 years. The ...
1
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1answer
49 views

NI-MH battery monitor design. Any obvious errors?

Let me preface this by saying I'm not that much of an EE expert, this is a "hobby" project, I consider myself as knowing enough to be dangerous. ;) I'd never apply for a full time career as an EE ...
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1answer
90 views

What happens when the voltage drop does not equal voltage rise in a closed series circuit?

New to electronics. Can't get my head around so many basic things but the application of KVL is bugging me the most. I want to know what happens when Kirchoff's voltage law is broken. If for example, ...
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2answers
52 views

Voltage Dividers in a pull-up resistor circuit (why does the pin go to low)

I understand that when the button is in its open state the voltage on the input pin should be fairly close to \$ V_{cc} \$ provided \$ R_1 << R_2 \$ as \$ V_{in} = V_{cc} \frac{R_2}{R_1 + ...
0
votes
1answer
88 views

Solar panel and 120mm Computer fan

Just before I start description my question, I would like to let you know that I am new at this. I am working on a solar air heater for one of my window. I've been researching and reading up on a lot ...
0
votes
1answer
76 views

Series and parallel transformers?

I have two different transformers. The output of the first one is 15 volts and 1500 mA. The output of the second one is 5 volts and 500 mA. If I connected them in series (to get 20 volts) what will ...
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3answers
102 views

8V AC signal into 3.3V digital input pin

I'm a noob and I'm doing this to learn, basically. I have a typical old-style door bell with a transformer that outputs 8V AC, the wire the goes through the push button on the door and finally hits a ...
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5answers
113 views

How can a sensor apply a voltage?

(from http://www.adafruit.com/blog/wp-content/uploads/2009/06/tmp36pinout.jpg) Have a look at this picture. It's a simple heat sensor. Though it looks like it's really simple, I don't fully ...
0
votes
1answer
82 views

Relay that detects 240VAC and switches 12V DC

I'm wishing to detect the loss of AC power (in this case 240V) and when this event occurs have a 12V DC circuit go to earth. This will trigger an alarm for users to react to situation. Can anyone ...