All Questions
85
questions
1
vote
3
answers
86
views
Decent MOSFET for a beginner to learn from?
I am relearning MOSFETs, but more importantly I would like to focus on building some basic circuits and learning practicality over theory. I have a BSEE but haven't spent much time outside of class on ...
- 11
4
votes
2
answers
731
views
Why does LT Spice simulation of AD711 op-amp show a non-zero output voltage when inputs not connected?
I am studying designing circuits. I got a strange problem with LT Spice.
I didn't connect any inputs into the amp but the result showed output...
I couldn't understand why it had the output voltage.
...
- 43
2
votes
1
answer
67
views
Bias Voltage affecting op-amp at 0v
This question is a follow-up from the setup described here
Recap: I am designing a circuit which is intended to map a signal in the 0-5V range to the 1.75-7.0V range. To do this I am using an LM317T ...
3
votes
3
answers
123
views
Selecting appropriate Opamp for RRO applications
I am designing a circuit which is intended to map a signal in the 0-5V range to the 1.75-7.0V range. To do this I am using an LM317T voltage regulator in conjunction with a TLC2272 Rail-to-Rail opamp. ...
1
vote
2
answers
64
views
LTspice: Troubleshooting a common emitter amplifier
This is a screenshot of a common emitter amplifier my instructor made in LTspice (everything is working fine):
This is my attempt to make the same circuit (it isn't working, there's no amplification ...
- 175
2
votes
0
answers
161
views
Simulation of transimpedance amplifier in LTspice
I am trying to simulate a circuit that is presented in a research paper by Dr Behzad Razavi. I am using LTspice for the simulation (please see the attached image and netlist for the circuit).
I am ...
- 150
0
votes
2
answers
95
views
Class-AB Power Amplifier not working in LTSpice
So we were asked to create an audio amplifier simulation in LTSpice. We decided that the total gain of the circuit should be around 600, having four stages in total: differential amplifier, CE ...
1
vote
2
answers
121
views
No DC offset observed in the CE amplifier circuit part
The objective is to make an audio amplifier. We have decided to make one that has four stages: a pre-amp with a gain of around 120, the next one is a CE amplifier with a gain of around 5, the third ...
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
2
votes
0
answers
103
views
What is the point of analysis and biasing calculations when real world performance is going to be much lower in analog circuits? [closed]
I am making a 3-stage audio amplifier as a course project. The first stage is a differential amplifier, the second stage is a common-emitter amplifier, following that there is a passive filter and ...
- 505
1
vote
1
answer
90
views
Floating node of amplifier in LTSpice
I have been trying to create an actively loaded degenerated CS amplifier with current mirror in LTSpice and whilst working on other aspects of the amplifier the Vout node decided it was floating. I'm ...
- 21
1
vote
1
answer
273
views
CD4007-based subthreshold MOS amplifier
I'm considering buying a pair of CD4007 ICs so that I might build a subthreshold NMOS amplifier.
I've seen it discussed here.
I'd like to build this circuit depicting a simple subthreshold amplifier.
...
- 463
3
votes
3
answers
119
views
AB amplifier, spice not giving what I expected
Boy, I've copied this common circuit from elsewhere and spice is giving me this strange result. Below are the two voltages on the bases in blue and green. In red is Vout. I'm puzzled why Vout is only ...
- 57
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
2
votes
1
answer
596
views
Simulation of JFET Amplifier in LTspice
I followed a guide by FesZ Electronics on biasing a JFET amplifier and came up with the following circuit:
simulate this circuit – Schematic created using CircuitLab
I then hooked up to a 0....
- 127