All Questions
63
questions
3
votes
2
answers
577
views
Why Is The Voltage and Current Not What I Calculated?
I'm new to electrical engineering and created this simple AND gate in LTspice.
This LED has a max of 2.1V and 120mA.
I calculated the resistor using the formula R=V/A=(5V-2.1V)/0.12A=25 Ohms.
If you ...
- 67
0
votes
0
answers
49
views
Questions about eliminating oscillation and noise in a load cell system
I'd like to ask you for your expertise on a challenge I'm facing as part of an electronics project.
A crucial part of this project is the integration of a force sensor, whose variation in resistance (...
3
votes
1
answer
100
views
Operational amplifier question in LTspice
I was asked to pick values for the resistors (I picked R2 = 78 Ω and R1 = 2 Ω) and for Vminus and Vplus.
Can someone please explain what these voltage sources are for and what values I should give ...
- 33
1
vote
1
answer
85
views
DC-DC converter possible by using Zener breakdown as input to transistor gate?
Suppose you have a DC voltage source that is higher than required, in this example let's assume one wants a 12V voltage source from a 18V source. Would it be possible to have a circuit, where the ...
- 11
-2
votes
2
answers
204
views
Impulse response ltspice
Is any one able to explain why I am not getting an impulse response when I probe across L1? The voltage shown seems to be the same no matter where I probe on the circuit.
6
votes
5
answers
4k
views
How does this voltage doubler obtain a higher voltage output than the input of 5 V?
I've designed a basic schematic using a 5 V AC source.
Upon simulating this circuit, I observed that the voltage between D1 and C3 registers at +9.55 V, while between C4 and D4, it measures at -9.55 ...
- 105
1
vote
3
answers
1k
views
Why can't I charge a capacitor using a N-FET as switch
I'm new to MOSFETs and LTspice, but I have an N-MOSFET working as I would expect with resistive loads, I’ve had step like input on the gate too and all seems good, but whenever I put a capacitor in ...
- 667
0
votes
1
answer
44
views
ZXCT1082E5TA current detection circuit
I am trying to create a USB inrush detection circuit using ZXCT1082E5TA shunt current sensor. I want to control a 3.3 V signal, when new USB device is inserted. I did some research about inrush ...
- 433
3
votes
4
answers
1k
views
What is the reason for getting 7.8 V as output in between two circuits with two voltage sources?
Since I am beginner to circuit design, I am in progress of understanding different basic circuits behaviour.
I designed the below switching circuit with clear transistor calculation. I am using this ...
- 627
2
votes
1
answer
221
views
I have simulated this constant current circuit on Lt-Spice, why do I get so low values for current output?
I used a Howlands current pump inspired model using two op-amps, and my goal is to get a constant current output for load resistance range of 500-3000 ohms. The circuit I found uses A PWL voltage ...
- 21
0
votes
1
answer
1k
views
Designing a PID controller using uA741 opamp using ltspice [closed]
I want to design a PID controller I created the design with all the components but when I run my ac sweep my output graph of Vout/Vin is not correct as a PID controller should function but when i run ...
2
votes
2
answers
180
views
Voltage drop of a p-channel mosfet
I am adding reverse polarity protection to my circuit. I can simply use a diode/schottky diode to do that; however, my main concern with a diode is its voltage drop. Therefore, I am considering the P-...
- 125
1
vote
1
answer
107
views
LTspice 1000A simulation
I want to simulate a 1000A current flowing through a circuit in LTspice. The supply voltage is 230V AC @ 50Hz. This circuit will also have 0.05 milliohm in series with the load (this resistor acts as ...
- 2,391
0
votes
0
answers
42
views
Troubleshooting circuit design for sensor input and desired output range [duplicate]
I designed a circuit to process input from a sensor with a range of -300 mV to 300 mV. The desired output of the circuit is 0 V to 600 mV. To achieve this, I used the op-amp equation Vout = Vin + 0.3 ...
- 87
2
votes
1
answer
4k
views
How to calculate small signal gain with LTspice?
For my homework I need to find the small signal gains of the circuit below.
For the first part of the circuit the small signal gain is calculated with
$$A_{V1} = \frac{u_{a1}}{u_e}$$
and for all of ...
- 35