Tagged Questions

-1
votes
2answers
117 views

threshold problem on a Schmitt trigger op amp

I have the Schmitt trigger op amp on the below diagram. (channel A & B refers the oscilloscope probes on the following figures). The resistor values are selected to set the trigger threshold as ...
1
vote
1answer
67 views

connection from an comparator to an optocoupler

I have the circuit below to decode a signal that is defined as Logic high >9.5 V and Logic low <6 V To determine the ...
1
vote
1answer
73 views

Voltage drop from poor connection

In a DC circuit, why does an open circuit voltage drop appear across a bad connection? For example i have 48vdc wires where a connector is charred from bouncing/bad contact. Under no load the side of ...
1
vote
2answers
79 views

Mosfet Circuits Voltage

So let's take a simple cmos circuit like this: So I get that for DC analysis \$V_G = 12 \frac{R_2}{R_1+R_2} \$ and then \$ V_{GS} \$ makes sense to me...because there is a constant \$ V_G \$ value ...
0
votes
3answers
112 views

Serial and parallel circuits and power

If I have 12V of power, and wanted to power LEDs with a forward voltage of 2V, could I only power 6 of them? Would I connect the cathode of one to the anode of the next, creating a kind of serial ...
1
vote
2answers
83 views

Circuit analysis with nodal analysis

[EDIT] I'm going to give mesh analysis another go, and see where that gets me. [DOUBLE EDIT] Mesh analysis didn't get me anywhere :( Im tearing my hair out over this problem, so any help would be ...
2
votes
1answer
82 views

What is the voltage at a node between two series voltage sources?

Hopefully the title explains it. As an example, what is the voltage at node one in the schematic below? And more importantly, why? I believe the answer is 0V, but I suppose what I'm thinking is: Why ...
1
vote
1answer
186 views

Simple circuit Voltage regulator question?

I am trying to build a simple circuit that takes a 9v battery through a voltage regulator that outputs 1.5v across a load resistor . The load will be just a piece of metal that gets heated up. My ...
3
votes
3answers
219 views

Parallel and Series Circuits Question (Electron Flow)

So this is a pretty basic question, I understand the aspects of parallel and series circuits but don't understand why? For instance: How can the Battery be "drained" faster when say 3 LEDS are ...
2
votes
3answers
275 views

How do I calculate the gain of an op-amp summing amplifier?

So if I have a summing amplifier circuit like the one below: I know the Vin1, Vin2, and Vout value and the circuit is designed such that Vout = -(Vin1+2Vin2) but how do I calculate the gain? I know ...
3
votes
1answer
120 views

How do I calculate the voltage at these locations?

I'm wondering how to calculate the voltage on the following charts (series circuit and parallel circuit). I'm interested in the math process involved, not the answer. I'm mostly confused about how ...
2
votes
2answers
355 views

How to remove 20MHz SPI signal noise?

I did some SPI software configuration for my DSP board. Then I soldered several missing 0 ohm resistors onto the board so I can tapping the SPI signal from pin headers. Then I measured the SPI Chip ...
0
votes
1answer
313 views

Where exactly do the electrons go in the circuit once they traverse the circuit elements?

From my understanding, when a voltage is applied to a circuit the free electrons in the circuit elements start moving towards the higher voltage potential. So what happens once the electrons reach the ...
0
votes
3answers
503 views

Why is the voltage across a reverse biased diode equal to source voltage?

Why is it not equal to zero since a reverse biases diode is essentially an open circuit?
0
votes
2answers
360 views

What is meant by relative voltage?

Suppose you have a circuit ,you are told that the voltage at point 2 relative to point 1 is -90V, the voltage across R2 is -30V and V0 is 200V. What is the meaning of voltage at 2 relative to 1? ...
1
vote
1answer
151 views

What's passive about the passive sign convetion?

I've heard and read about the passive sign convention, but don't really understand its meaning and importance in solving electric circuits. Is this because of conventional current which flows ...
6
votes
4answers
544 views

MOSFET Switch w/ Fast Settle Time for Switching E-Field

Application: I have a copper mesh (10cm x 10cm square) in a vacuum chamber connected to a BNC connector by a 24-cm-long copper wire. The goal is to switch the mesh voltage (referenced to ground) from ...
0
votes
1answer
77 views

which battery will supply the load?

I have connected 14V supply terminal from alternator to 12V battery terminal and has taken the load across these terminals . But the load is operating still in 12V, and when measured across the ...
0
votes
1answer
265 views

MOSFET sub-threshold operation

I have a question related to the sub-threshold operation of MOSFETS. Let's say I have the following setup: How can I calculate the sub-threshold current ( Id when Vgs < Vgs(th) ) at Vgs = 0.5V ...
1
vote
3answers
225 views

what is the magnitude of total voltage in the below circuit?

I was working on some RLC circuits and I found a question something like this. In series RL circuit, \$V_R\$ = 4V and \$V_L\$ = 3V. what is the magnitude of total voltage ? I just thought \$V_T\$ = ...
1
vote
2answers
185 views

Thevenin Resistance?

I don't understand our professor's explanation for the answer to this problem: An LED is connected in series to a 150ohms pull up resistor and a MOSFET with drain-source resistance of 3ohms. The Pull ...
3
votes
4answers
302 views

Simple voltage divider question

So two resistors in series can be a voltage divider. So say I have the following circuit - From what I have read the voltage gets split across the resistors based on their resistance. So there will ...
0
votes
2answers
6k views

Potentiometer to change voltage?

How can we use potentiometer to regulate voltage form o-5v? That is, if we rotate the potentiometer it will give some voltage variation as output. If there any circuit available please let me know ...
2
votes
6answers
204 views

Calculating Voltage

I am trying to calculate the voltage \$Vw\$ of the following circuit: I have little experience with these kind of problems, so I tried to solve first a more simple circuit that did not include the ...