All Questions

Filter by
Sorted by
Tagged with
-1
votes
2answers
140 views

Why do we have exactly three parameters to describe relationship between current and voltage in linear elements?

I was simply pondering over everything I learned about circuits and electricity and there was this one question I couldn't give a simple answer to. Why exactly do we need only these three parameters ...
-1
votes
1answer
295 views

Capacitor's energy(J)=F•V²/2 Why divided by two?

So if use these two equations: $$J=C\times V$$ and: $$F=\frac{C}{V}$$ I get: $$J=F\times V^2$$ Then why is it divided by two? Is it always like this or only for capacitors?
-1
votes
2answers
8k views

Hexagonal resistor circuit (equivalent resistance ) [closed]

I've already find the equivalent resistance between A en B by Star-Triangle transformation , but can someone just explain how can i handle it by Symmetry,asymmetry network analysis ? all the resistor ...
-1
votes
2answers
173 views

555 Timer duty cycle changing formula

I am making a PWM motor speed controller. I used the Astable mode thinking it would work; it did not. Using an oscilloscope I noticed that I am only changing the frequency not the duty cycle by ...
-1
votes
1answer
103 views

I need to know what diode to use to protect a 9V battery when connected directly to a 12V battery ( +to+ and - to -) [closed]

When connecting a 9V battery to a 12 volt battery what diode do I need to protect the 9V battery?
-1
votes
1answer
179 views

Electric potential in a cicuit

Look at the image at (http://sub.allaboutcircuits.com/images/00082.png). Ignoring all the resistors in the diagram and assuming that the charged particles flow as arrows show, why does the electric ...
-1
votes
2answers
342 views

Integrate residential hardwired alarm zone with modern wireless sensor

I have an old alarm system in my house that I would like to integrate with a modern system. The old system has hardwired circuits where multiple reed sensors in series monitor a zone with as many ...
-1
votes
1answer
62 views

Energia/MSP-EXP432 Issue: Analog In Pin removing voltage from Voltage Divider

In the circuit below, I want to measure the voltage going to the ADC (output from the voltage divider consisting of a fixed resistor and photoresistor) using an MSP-EXP432; however, the MSP-EXP432 "...
-1
votes
1answer
121 views

What does "LB" out mean in a DC-DC buck converter?

Teacher gave me a schematic,and it includes a DC/DC buck converter with "LB" input and output,but i have no idea what the "LB" is,so i want to ask that does someone know what may the "LB" be?
-1
votes
3answers
758 views

Most efficient way to power a LED (with 2 modes) using CR2032?

It's new for me to actually ask a question here instead of only reading which I did appreciated a lot in college. I have a background in mechanical engineering and do have some (low level) experience ...
-1
votes
1answer
5k views

Bluetooth Interference with High Pitched Tone

i'm building a portable stereo system and am having some unwanted noise from the bluetooth receiver. the noise is typically a high pitched tone. please see the attachment for my chicken scratch ...
-1
votes
1answer
464 views

Switching from battery to usb power source [duplicate]

I'm currently creating a small device to operate on a CR2032 battery when it is disconnected and a USB power when it is connected. I want the device to be powered by USB when it is connected, without ...
-1
votes
1answer
496 views

Peltier cold temperature does not transfer when a heat sink is attached

I am trying to build a peltier cooler. It works. Cold side temperature is about 10C on cold plate of peltier. I want to blow this cool air out. But the cold temperature goes up as soon as the ...
-1
votes
2answers
3k views

Finding proper motor for lead screw lifting?

I need to lift amount 0.6 kilogram up to 20 cm in 2 second with Permanent Magnet DC Motor with PWM speed control driver ,for this device: So i have one PM dc motor with 300 RPM MAX,12 V and 2 Watt ...
-1
votes
4answers
5k views

Twin T active notch filter [closed]

So I know that this a band reject filter with the quality factor of Q I have two questions: 1-Why in one T the resistance is half the other resistances in the second T. 2- How would adding a ...
-1
votes
2answers
184 views

Why are VOL and IOL seperately defined in I2C and SMBUS?

What is the point of defining VOL and IOL separately in I2C and SMBUS?
-1
votes
1answer
234 views

MOS Current Mirror

I was investigating a MOS current mirror on the photo however i could not understand how the equation (3) was obtained from equation (2). I put a question mark also there on the photo. My second ...
-1
votes
1answer
5k views

Max discharge rate of Alkaline AA batteries?

I'm in a bit of a tight situation, as I need a new battery pack for an upcoming competition, so I've tried to make my own. I put 7 of these: http://www.amazon.com/Rayovac-Alkaline-AA-Batteries-36-...
-1
votes
5answers
124 views

BJT current distribution

I asked a similar question here a few days ago. I'm asking this question here again because the answers were ambiguous. Consider the first picture, no collector battery, only a base voltage is given. ...
-1
votes
1answer
2k views

Op Amp output range

Consider the following scenario: The supply voltages of op amp (rail to rail) is 5V. Amplification factor of the op amp is 100. Which means if the input is 0.01 volt, the output will be 1V. If the ...
-1
votes
1answer
98 views

How to design a transistor voltage divisor amplifier with a load resistance of 100 ohms?

I am trying to design a transistor amplifier with a load resistance but I have a lot of problems because the load resistance is very low. I can't change the value of it. I have read a lot about it but ...
-1
votes
2answers
774 views

Can a secondary transformer winding output too much current? [closed]

Most household appliances operate with a step-down transformer if I'm correct where they decrease the voltage. Consequently, the current will be relatively high in the secondary winding, but this is ...
-1
votes
1answer
72 views

Oscilloscope and probes [closed]

What effect , if any, has using a x10 probe on: Voltage reading of oscilloscope with resistance box set to zero ohm? Voltage reading of oscilloscope with the resistance box set to 900k Ohm? And what ...
-1
votes
1answer
116 views

Identification question - tiny SCR & colorful Zener? [closed]

Update: The transistor with 3D marking is really an NPN, not a PNP. I found the exact model at https://www.google.com/search?q=pnp+3d+transistor&tbm=isch&source=univ&sa=X&ved=...
-1
votes
1answer
1k views

HDB3 Waveform: Determining the bit sequence

I was asked to determine the bit sequence of a given HDB3 waveform. I understand that if there are three consecutive 0's then the fourth in that sequence must be a violation pulse. In this example ...
-1
votes
1answer
323 views

Buck-Boost power supply I_ripple calculation

I'm not looking to get torn apart, just looking for a hand. I can't remember exactly how to calculate the RMS Current required from the output capacitors or a Buck-Boost power supply and I was hoping ...
-1
votes
2answers
510 views

My first transformer causing safe fuse to go out

I found a fairly big, old transformer. I unwinded all the coils and winded them again. My primary coil has 20 turns, and the secondary coil has 200 turns. I didn't use any tools while doing this, so ...
-1
votes
1answer
202 views

Using a laptop to communicate with an MBED module

I'm using an external power source to power an MBED module. I have the UART transfer and receive ports connected to a MAX232 level switcher in order to make the signals compatible with RS232. From ...
-1
votes
1answer
210 views

Is there a full list of the names & abbreviation of electronic components [closed]

I came by a few electronic components that I don't recognize them from their shape nor their letters printed on the PCB. Is there a full list of the names and abbreviation of electronic components? ...
-1
votes
2answers
3k views

BJT characteristic curves -- generating them

I know that the relationship between the base current \$i_B\$ and the base-emitter voltage \$v_{BE}\$ is given by the Shockley equation. \$i_B = I_S (e^{v_{BE} / V_T} - 1)\$ This is the input ...
-1
votes
1answer
108 views

Which load resistance is connected to generator U2?

I have this op amp and one of the questions says Which load resistance is connected to generator U2? This is my attempt but I can not confirm if it right. No it's not homework, it examples I'm ...
-1
votes
1answer
1k views

Can C547B transistors be used to build H-Bridge?

I've collected many C547B transistors from an old UPS, Can I use these to build h-bridge to control DC motors from Arduino?
-1
votes
4answers
546 views

Can you connect a microcontroller to USB without USB built into the chip?

I have a microcontroller that I don’t know if it has USB capability built in but I don’t have the money to get one that does. Is there any way of either software to directly read an IO pin or use ...
-2
votes
1answer
179 views

What's the thick wide aluminum tape used for in last mile grid transformers?

This YT video (scrolled to 0:45) shows the process of fabricating a pole mount transformer. At 0:45 the following is shown: there's a wooden brick used to hold everything together, it's covered in ...
-2
votes
3answers
674 views

Converting a square wave into a sine wave

I have been researching methods for converting a square wave into a sine wave, but I cannot seem to reach a conclusion. Is it possible to preserve the amplitude and frequency of a square wave when ...
-2
votes
2answers
162 views

Voltage regulator and Kirchhoff current law

In a linear voltage regulator like a TO-220: does Kirchhoff current law apply? What is the equation for the three currents flowing? In other words, what is the relation between I1, I2, I3 in the ...
-2
votes
1answer
192 views

Is a ferrite sleeve better than a low-pass filter in order to protect a PCB from EMI caused by lightning

Follow up from previous post. This post is different because I am now focusing on the power cable and thus the power input of the PCB. This post is related to the EMI produced. I wrote a different ...
-2
votes
2answers
127 views

Voltage regulator current and heating

Many texts I read take (Vin - Vout)*Iload i.e the current Iload is I3 in the below figure when calculating temperature of a regulator: But I3 is not exactly same with I1 there is something called "...
-2
votes
3answers
538 views

How to reduce maximum power rating of dishwasher for use with photovoltaics inverter? [closed]

I have a photovoltaic power system and an inverter with an overall power rating of 1500 Watts. I want to connect a dishwasher which consumes 2200 Watts when heating the water. Question: What is the ...
-2
votes
1answer
232 views

Arcade stick PCB not working as expected

I am using Logitech precision PCB to make an arcade stick. I am having a problem in button 1 (green) area. While I try to solder button 1 via R2, I had a great difficulty - R2 resistor moved every ...
-2
votes
2answers
138 views

Can I control 6-7 devices of 12v max (each) with Arduino Uno?

I have to control following devices: 2 × Gear motors (each 12V, 200mA, speed & direction) 1 × Motor (12V , 1.2 A, on / off) 1 × Motor (3V, 110mA, on / off) 1 × dc pump (...
-2
votes
2answers
147 views

Can synchronous data transfer be used for transferring large data in case of computer architecture and organization? [closed]

I am learning computer architecture and organization. I have this confusion, can synchronous data transfer be used for transferring large data in case of computer architecture and organization? I ...
-2
votes
4answers
297 views

Can I safely ground myself by clipping an anti-static wristband to a half-inserted plug?

I'm having some trouble grounding myself for laptop repair. I cannot get the crocodile clip of my anti-static wristband in to my plug socket (I'm in the UK, so our sockets are a bit difficult) and I ...
-2
votes
0answers
145 views

Basic audio amplifer circuit with transistors [duplicate]

Possible Duplicate: Simple Audio amplifier Using Transistors I'm looking for a basic audio amplifier(1w - 0.5w) circuit which is designed with transistors. Could you help about that?
-2
votes
1answer
113 views

DC DC converter

I am newbie trying to build a circuit, please help me out. I am trying to build a DC-DC converter whose input will be 24V and output would be 5V 3A. I have picked AP63301WU-7 DC DC converter from ...
-2
votes
3answers
966 views

Using a digital potentiometer with a SMPS?

Is it possible to use a digital potentiometer with an SMPS, to adjust the voltage? I'm looking at one with a 2 MHz -3dB bandwidth. What does this mean for a 300 kHz switcher?
-2
votes
1answer
178 views

Design of carry chain -- Problems with clock's in design

I am trying to implement carry chain on FPGA and i want that resault from each block is written in register. Each block is 10 bit adder with following code: ...
-2
votes
3answers
866 views

How to find the frequency of any device? [closed]

Are there devices which can figure out at what frequency every device transmitting radio frequencies operate at precisely? Say from a high of 2.4 GHz microwave to a low of 402 Hz pacemaker.
-2
votes
2answers
133 views

Current Divider Question

Knowing all the values of resistances, capacitances and the value of the current source is there a way to find out how current is split in the two branches?
-2
votes
1answer
155 views

Voltage drop remaining voltage [duplicate]

According to here the resistance drops liniar along the path. In scenario 1 at the start of R1 the resistance the current encounters is 100\$\Omega\$ and at the ...

15 30 50 per page