11
votes
Accepted
Can't get 5V 3A DC constant
It seems you are making several beginner's mistakes in your understanding and application.
You are using the LM2956 5.0 which is the 5 V version. This will output a regulated 5.0 V subject to meeting ...
- 159k
8
votes
Accepted
Why is series LC circuit not behaving as band pass filter?
That's the problem with simulating with "ideal" components — you see behaviors that you would never see in the real world.
Your circuit has no resistance in it anywhere. The function generator ...
- 164k
7
votes
Converting a circuit from Multisim into a PCB
NI Ultiboard is the PCB layout counterpart to Multisim and allows you to layout PCBs from a Multisim schematic.
- 71
7
votes
Voltage in an inductor - DC circuit
When the switch goes open-circuit, the inductor tries to keep the same current flowing AND in the same direction. The only way it can achieve this is by making its upper terminal go negative. So, at ...
- 380k
7
votes
Accepted
Series Parallel batteries
Please help me out.
It's quite simple; don't put voltage sources directly in parallel. If you want to do this less directly, use a small value series resistance for each battery. 1 μΩ would do (even ...
- 380k
7
votes
Series Parallel batteries
When you ask a simulator to solve a circuit, it has to be able to find everything. As the voltage sources you have used are zero impedance, a loop of voltage sources could have an undefined current ...
- 140k
6
votes
This is not my circuit, but anyway, What are they?
The points labelled A, B and C are likely to be test points, to test the function once the circuit is built.
The V+ and V- are most likely the connections for the input, given the two power sources ...
- 5,141
6
votes
This is not my circuit, but anyway, What are they?
By way of a direct answer, \$A\$, \$B\$, and \$C\$ are in fact required test points. \$C\$ is actually also an output as well as a test point.
There is NO possible way to properly adjust the ...
- 69.1k
6
votes
Can't get 5V 3A DC constant
You are measuring the circuit incorrectly. Your ammeter is shorting the output, this is why you are getting maximum current.
You need a proper load, the LED is not going to work. Use a resistor ...
- 11.5k
6
votes
Accepted
Pre-amplifier for speaker
Make the 3 capacitors at least 100X bigger.
And remove that 8 ohm load.
Then resim.
You have about 0.3 volts across the Remitter. Thus about 1mA.
That makes the 'reac', which is 1/gm, be 26 ohms.
Now ...
- 32.7k
6
votes
Accepted
How can I verify the max power theorem in a buffer opamp?
Your first circuit has a 3:1 voltage divider.
Your second circuit doesn't. The op-amp input impedance is so high that the 2k resistor makes no difference. It sees the full 1.5 V of the battery.
- 159k
6
votes
LM7805 for stable 5V output
The LM78xx series of voltage regulator have dropout voltages of 1.5 to 2 volts. All linear regulators have at least some dropout voltages, which restricts them to always having output voltages lower ...
- 35.8k
5
votes
Inverting Op Amp: Why does current flowing into output seem to magically reappear at ground?
Trace both current paths from output, and you find they both end up at ground. Via R3 directly, and via R2, R1 and V1.
So if the output sinks current I, that current must come from ground. Simple as ...
- 65.8k
5
votes
5V power supply using 7805 with multiple outputs
It doesn't matter how wire you connect to the 7805's output. The only things matter is how much current you will ask for. According to the datasheet, the 7805 can provide 500mA. This mean the sum of ...
- 3,828
4
votes
Accepted
Push-button BCD counter circuit
You are apparently on the right track. Now all you need is a binary counter that resets when it gets to 9. That's a total of 10 discrete steps (0..9)
Basic theory should have told you that you need ...
- 22.6k
4
votes
Questions on Multi-stage transistor Op-Amp
It will be hard to explain this circuit if you don't have much background in electronics. Q1 and Q2 are a differential input pair. R7, R8 and Q3 create a constant current. So the constant current ...
- 24.2k
4
votes
Accepted
What's wrong with this RC Phase Shift Oscillator?
The third phase shift stage (that is closest to Q1's base) is "ruined" by the biasing resistor R2. R2 is in parallel with R8 and it greatly reduces the value of R8. Instead, remove R2 and make R5 much ...
- 380k
4
votes
How to design over voltage protection Crowbar Circuit?
Explaining the Simulation Results
You don't show your calculations. That's a problem. You compute resistor values to almost insane precision. That's a problem. You don't take into account that an SCR ...
- 69.1k
4
votes
Accepted
Why is the oscilloscope in Multisim software showing more voltage than the source?
See the green circles I've added below: -
You are using too big of a maximum time step in your simulation. Try lowering it.
- 380k
4
votes
Accepted
Can electric circuit simulation software simulate capacitor charging process
Since you measure 12 V the capacitor is already charged, which is as expected because the simulator tries to find the steady-state solution. The 12 pA shown is likely a leakage current, either ...
- 12.7k
4
votes
Can electric circuit simulation software simulate capacitor charging process
With a capacitance of 1 F and a resistance of 1 MΩ, your circuit's time constant is
$$ \tau = RC = 1\,\mathrm{F}\cdot 1000000\,\mathrm{Ω} = 1000000\,\mathrm{seconds}. $$
You would need to simulate the ...
- 7,101
4
votes
Accepted
Voltage in an inductor - DC circuit
Just to show:
The inductance is here 10mH and the input voltage V1 is 10V for easy calculations.
The timed switch SW1 starts to conduct at t=10ms and stops at t=50ms. The inductor has zero resistance,...
- 21.2k
4
votes
Accepted
How to determine what kind of response this filter has
Because you have the transfer function with all parts values you can compare this function with the general function - expressed NOT with coefficients (which have no direct relation to the kind of ...
- 22.5k
4
votes
How can I generate an exponential signal in simulation software?
In spice you have behavioral current sources (bi).
- 10.2k
3
votes
Why am I not able to simulate a circuit as it is given in a problem?
You've installed V1 "upside down" in the simulation. The long bar is the positive terminal, the short bar is the negative.
One simple mnemonic is that the long bar is "more" than the short bar, so ...
- 130
3
votes
Inverting Op Amp: Why does current flowing into output seem to magically reappear at ground?
I'm pretty sure the Boyle macromodel for 741 is causing this. In Op Amp Applications Handbook (ed. Walt Jung) p. 742 the MPZ model (well AD's flavor thereof) has this praise
output load current is ...
- 14k
3
votes
Accepted
Full wave bridge rectifier circuit in multisim
Your voltage source V1 has a peak voltage of just 1V, your lecturer had a voltage source of 10V. In a bridge rectifier circuit the current has to flow through 2 diodes which will have a voltage drop ...
- 5,185
3
votes
PCB design: how to route through hole connectors with tightly fitted pins?
No matter what you end up doing, you will probably end up needing to make 'escape routing' to the outside some way or other (multiple layers with a consistent escape strategy for example) and then ...
- 6,038
3
votes
5V power supply using 7805 with multiple outputs
It doesn't matter how many connections you connect to the output of the 7805, each connection will have 5V.
The important thing is how much current you draw from the 7805, depending on the combined ...
- 1,634
3
votes
Accepted
How do electronic design tools work
If you really want to understand this, I highly recommend a book by Dr. Farid Najm, called "Circuit Simulation". If you follow the exercises in the book you can code a working simulator by the time ...
- 19.5k
Only top scored, non community-wiki answers of a minimum length are eligible