24 votes
Accepted

What numerical methods are used in circuit simulation? How can I get an overview?

For an overview of numerical methods in circuit simulation, I'd suggest reading some of the published SPICE papers, and in particular Laurence Nagel's exemplary PhD thesis: Nagel, Laurence W., SPICE2:...
  • 7,439
11 votes

What numerical methods are used in circuit simulation? How can I get an overview?

Because most interesting circuits are non-linear the nodal equations can't be solved directly by straightforward methods (eg. LU decomposition), so Newton-Raphson method is applied to converge to a ...
9 votes

What numerical methods are used in circuit simulation? How can I get an overview?

Most of them use either the plain trapezoidal approximation or Gear integration. LTspice specifically also has a proprietary modified trapezoidal method that they claim is less prone to spurious ...
  • 22.9k
7 votes

Trying to develop a peak detector circuit

You probably want a peak detector with decay, you don't want to hold the peak "forever". You need a resistor across C1. You probably also want a resistor in series with C1 so the the opamp ...
4 votes

How will be the energy consumption curve of a Li-Ion / Li-Polymer charger?

Short answer: No Longer Answer: What's written as power consumption (or delivery) of a device is always the maximum power consumption. In some cases it might be, what the devices really use but in ...
  • 2,589
4 votes
Accepted

Trying to develop a peak detector circuit

Why are the parts on your schematic so far apart? Your capacitor is missing a resistor parallel with it to discharge the capacitor between sounds. Audio opamps work much better when they are biased at ...
  • 2,803
3 votes
Accepted

Multisim results not matching handwritten results

I have found the issue. Multisim does not give a message when SPICE cannot solve inductors in parallel with no resistance. In order to solve the circuit above, you need to add a miniscule amount of ...
3 votes
Accepted

Parallel voltage sources (diode on one branch)

When V1 is less than or equal to 0.6 V, no current will enter the branch containing the diode. Since no other closed loop exists, the current flowing in your circuit will be 0. Now, apply KVL in the ...
3 votes

Are all resistors parallel in this circuit?

The five resistors are independant - neither series or parallel. As there are integrated circuits in the circuit, it does not make sense to determine a "total resistance" of the circuit. ...
2 votes

Can you explain intuitively why the pole exists in this common-emitter circuit?

I have looked at your circuit and and ran the fast analytical circuits techniques or FACTs over it. This is an intuitive method, which, in many cases, leads you to the answer without writing a line of ...
  • 16.6k
2 votes
Accepted

Voltage drop in a switching circuit with two storage elements

You can't meaningfully talk about V1 without referring to its reference node (0 volts). If that reference node is the negative end of source Vs then, V1 will equal Vs. If that reference node is ...
  • 405k
1 vote

Could anyone help me to analyze this diagram precisely, like a full explaination?

The first LED blinks at the clock rate of the 555 timer oscillator The 4017 is a sequential Johnson decade counter The 555 is a convenient and popular timer IC configured as an oscillator, with a ...
  • 3,353
1 vote

Trying to make an ammeter to measure 5mA of current and having some difficulties and confusions

Your calculation is correct, to measure 5 mA full scale on a 1 mA 130\$\Omega\$ meter you would need 4 mA to go through the shunt, that's $$\frac{1mA\cdot130\Omega}{4mA} = 32.5\Omega$$. In your test ...
  • 8,157
1 vote

Trying to make an ammeter to measure 5mA of current and having some difficulties and confusions

Can your power supply deliver 0.13 V accurately? As you are developing a current meter, it would be better to supply it with a current. Perhaps set the power supply to 5 V, and use a resistor in ...
  • 148k
1 vote

Finding current flowing through voltage source in a circuit with two storage elements

Well, it's not hard to see that: $$\text{I}_\text{source}\left(t\right)=\text{I}_{\text{C}_1}\left(t\right)+\text{I}_{\text{R}_2}\left(t\right)\tag1$$ Where: $$\text{I}_\text{source}\left(t\right)=\...
  • 5,575
1 vote

Trying to develop a peak detector circuit

It looks like the simulator is trying to guess the starting voltage of the capacitor (the so-called "DC operating point") and when the capacitor is larger it guesses a bigger value. If you ...
  • 8,657
1 vote
Accepted

Why do we need an interrupts when using a battery charger?

A subsystem will issue an interrupt to a controller when it needs to asynchronously indicate a service request. Any reasonably complex subsystem will have logic that will need to be serviced either ...
  • 5,737
1 vote

Parallel voltage sources (diode on one branch)

The current across a diode (taken positive for current flowing in p-side of diode) in series with a resistor R can be written as I=max(0, Vdiode/R) [i.e. mathematical way of saying current cannot be ...
1 vote

Multisim results not matching handwritten results

All this time I was looking at the simulation but, it looks like you got the calculation wrong: at the very last step, after correctly calculating the current for \$Z_2\$, you divide that current by 2....

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