Questions tagged [analog]
Analog circuits have a range of voltages, rather than just two as in digital logic.
2,667
questions
0
votes
0answers
29 views
Modes of operation of P-JFET
I have the conditions of the operation of the N-JFET
But I can't understand how we can find the expressions for the P-JFET.Are they opposite?Help appreciated
1
vote
2answers
66 views
Have I obtained the correct simplified transfer function for this RLC circuit?
Have I obtained the correct simplified transfer function for this RLC circuit?
I am trying to obtain the transfer function for the following RCL circuit. However, the response of the TF that I obtain ...
0
votes
0answers
47 views
JFET question about operation
I have a question about the N-JFET.Assume it operates at the linear region and it acts like a voltage controlled resistor. Can we say that if Vdg(drain-gate voltage) is increased then the resistance ...
0
votes
1answer
66 views
Pole at infinity and zero at finite frequency
Is there any circuit that has a pole at an infinite frequency and zero at some finite frequency? A first-order RC Low pass filter has a finite pole and zero at infinity and it makes sense, I am just ...
0
votes
0answers
25 views
IV characteristics of NMOS transitor
I have used the model of the GPDK90 transitor in Cadence. I have few questions regarding the IV characteristics:
Why does the threshold voltage change with change with Vds (Vds=
0, 1.25, 2.5, 3.75 ...
2
votes
2answers
66 views
Opamp Compensation For Input Capacitance
I am going through the datasheet of LM7171 for one of my applications. Please see the below circuit.
May I know how they arrived at the equation for CF?
Is this equation is valid for non-inverting ...
0
votes
2answers
130 views
Which is the input resistance of the second amplifier?
If a apply a positive Vs, then D2 is blocked and D1 is working, right? How do I calculate Vo then? I know the formula is: - (input resistance / negative feedback resistor) * Vs, but I don't know which ...
1
vote
1answer
34 views
Why am I getting “Grammatical Error” in LTspice?
Why am I getting "Grammatical Error" in LTspice the instant that my transfer function denominator goes from a 2nd order to a 3rd order system? See below.
Please note that the transfer ...
1
vote
1answer
38 views
ADC 1/2LSB vs 1LSB
I was going through the below question.
ADC first transition at 1/2 LSB - is that not a non-linearity?
I did not understand why they took the first transition point as 1/2LSB.if so then may I know the ...
0
votes
2answers
62 views
Analog Oscilloscope Flickering Signal Problem
I am using BK Precision 2125C Dual Trace Oscilloscope (30 MHz), which is analog. I'm trying to observe signal generated by the output of microprocessor. I'm seeing flickering signal (quickly moves ...
0
votes
2answers
27 views
Hall effect output to a level voltage or other useful output
I am trying to take the output of a Hall effect sensor (latching or non) that is sensing magnets on a wheel and turn it into a level DC voltage that varies with the speed of the wheel. The only ...
0
votes
1answer
40 views
Observation of negative voltage at the output of the op-amp
I am using ADA4898 op-amp.
Without connecting any elements to the circuit at the output of the IC, I see a negative voltage.
Is my IC broken?
simulate this circuit – Schematic created using ...
0
votes
4answers
78 views
Analog switches able to send bi directional digital information?
I'm trying to send digital signals from an ST-Link V2 programmer connected to my computer to a blue pill STM32 microcontroller, but I want it to go through a DG412 Quad SPST CMOS Analog Switch.
As far ...
3
votes
4answers
586 views
Op-amp homework question using potentiometer with my attempt at solving it
I nearly understood that when Rpot is 0, Vo is highest and when Rpot is 0, Vo is lowest.
So I tried KCL to get Vo when Rpot is 0 (0 turns).
I couldn't get Vo but just 0 volts. What mistake did I make?...
0
votes
1answer
36 views
simple MOSFET analog multiplexer
In my project, the 4051 switches two signal sources routed to the 4024 counter - an external clock signal and a manual advance clock (tactile switch). I thought that the use of the 4051 was overkill, ...
0
votes
0answers
44 views
Playback volume from old Sony voice micro cassette recorder is very low
I have an old Sony V.O.R M-529V microcassette recorder. It was found in a box packed away years ago.
I put in some fresh batteries and tried to play some old micro cassettes I had, but the play back ...
2
votes
2answers
141 views
BJT in saturation mode equations
Suppose we have this circuit:
simulate this circuit – Schematic created using CircuitLab
The BJT transistor is in saturation mode.Which are the equations which help us find the different ...
0
votes
1answer
52 views
How can I carry DC component to negative side?
I made a sine wave with stm32f407VG DAC periphal. But my sine wave has DC component 1.32V. I designed high pass filter but DC component was gone. But I don't want it to be gone. How can I carry it to ...
0
votes
2answers
59 views
Designing a common base amplifier to meet given specifications
I designed the circuit as below and I know that common base amplifier should have a unity current gain(usually <1) but I'm getting a very high gain. What might be the reason for this, is something ...
1
vote
1answer
108 views
What are the final steps to arrive at the transfer function for this RCL circuit?
What are the final steps to arrive at the transfer function for this RCL circuit?
I am attempting to arrive at this transfer function $$\dfrac{V_o(s)}{V_i(s)}=\dfrac{sL}{CL(R_1+R_2)s^2+(R_1R_2C+L)s+...
0
votes
0answers
20 views
Frequency plot with a node as reference in Proteus
I'm trying to make a frequency plot in Proteus of an inverse adder amplifier.
This is the schematic:
The thing is that when I use the frequency plot properties editor to change the property "...
-3
votes
1answer
72 views
BJT operation notes
Hello today we had a class in electronics and we discussed the BJT operation.Here are my notes:
Suppose we have this circuit:
simulate this circuit – Schematic created using CircuitLab
Ie = (Vb-...
0
votes
1answer
53 views
Constant Gain-Bandwidth product in amplifiers
Can somebody explain to me how the gain-bandwidth product is constant in an amplifier or op-amp? I want to know the mathematical expression behind it if possible.
As said here: https://en.wikipedia....
0
votes
1answer
55 views
Design a Cascode amplifier using suitable topology to meet the specifications( by Varying W/L ratio) . VDD is 3.3V
CONDITIONS
Output swing has to be at-least 80% of VDD (> 2.64 in this case) .
Power supply rails available are VDD and ground only.
Only one current source can be used in the design IREF = 50μA.
...
1
vote
2answers
67 views
Level shifting a 0-5V signal to 0-16V
I have a Atmel microcontroller with 0-5V DAC output and I want to shift it to 0-16V (16V max. normal between 11-16V).
It need an output signal with max. ~1mA, short protection and reverse polarity ...
-2
votes
3answers
68 views
Analog signal level shifting and opamp selection advice
I wanted to read out and output 5-ish volt analog signals from a 3.3v mcu.
So basically the signal (roughly 0.25v to 4.5v) first has to be level shifted "down", processed and then level ...
4
votes
3answers
120 views
What have I done wrong in determining the transfer function for this RCL circuit
What have I done wrong in determining the transfer function for this RCL circuit?
(1) $$\dfrac{Eo(s)}{Ei(s)}=\dfrac{s^2R_2CL+sL}{s^2CL(R_1+R_2)+s(R_1R_2C+L)+R_1} $$
Regardless, of how many times that ...
0
votes
2answers
101 views
Adding harmonics to the square wave means
I have generated two imperfect square waves by:
Adding fundamental frequency with 10 odd harmonics.
Adding fundamental with 20 odd harmonics.
What difference should I observe between two imperfect ...
0
votes
4answers
55 views
Single pole triple throw analog passthrough
I have a circuit that will simulate a device.
The device in question normally communicates by adding/removing resistance from a generated signal, the source of the signal will then measure the voltage ...
-2
votes
0answers
41 views
Schmitt trigger based NAND gate
If someone can help me to understand how to calculate the hysteresis of the Schmitt trigger-based NAND gate? Which MOSFET's dimension decides the Vth_H and Vth_L?
Thanks.
1
vote
3answers
108 views
Working principle of inductors
Assume we have this circuit:
simulate this circuit – Schematic created using CircuitLab
At t=0s we decide to close the switch, then current will start flowing through the circuit and around the ...
-1
votes
1answer
81 views
LTspice simulation with capacitors
I have this circuit simulated in LTspice :
simulate this circuit – Schematic created using CircuitLab
Here is the graph:
Why does the current flowing through R2 do that thing in the beginning (...
-2
votes
1answer
76 views
Capacitor voltage equation (partially charged initial state)
Assuming we have a RC circuit:
simulate this circuit – Schematic created using CircuitLab
We don't know the voltage of the capacitor but we know its voltage isn't greater than the battery ...
0
votes
1answer
63 views
Have I obtained the correct transfer functions for the following RCL circuit?
Have I obtained the correct transfer functions for the following RCL circuit?
Please note that my Maths is a little rusty!
$$\dfrac{Eo(s)}{Ei(s)}=\dfrac{1}{(R_1C_1L_1)s^2+(R_1R_2C_1)s+R_1} \tag{1}$$
...
0
votes
3answers
67 views
Named or Standard Circuits
BJT amplifiers have a few standard configurations, i.e. Class A, B, A/B. Likewise there are a variety of standard OP-Amp circuits such as summing circuits and filters.
Is there a publicly available ...
0
votes
2answers
61 views
4-20 mA sensor output to STM32 ADC input
I have a industrial sensor with 4-20mA output and I want to read that output from Stm32 ADC pin but I need suggestions to do that work in a nice way.
Can you guys suggest me the best way to do it? It ...
0
votes
3answers
60 views
Calculate diode voltage drop
I have studied the diode model which treats diode like elements with constant voltage drop and depending on the bias of the diode the voltage drop varies. Now I'm starting to learn about the correct ...
3
votes
2answers
127 views
Backward diodes VI curve
I am searching for the IV curve of a backward diode but couldn't find anything, any help?
0
votes
1answer
81 views
What should the transfer function be for this RCL circuit?
What should the transfer function be for the RCL circuit?
When I derive the TF (using complex impedance method) for Output voltage/Input voltage I get the following:
$$\dfrac{Eo(s)}{Ei(s)}=\dfrac{1}{...
2
votes
3answers
157 views
TL082 Voltage Follower
I just made a simple voltage follower using TL082. I applied 2.5V to voltage divider 100k and 25k, and apply that 500mV to positive input of TL082. But the output of follower is around supply voltage. ...
0
votes
4answers
136 views
Design of electronic lock
I am designing a electronic lock using a electromagnet(coil).This is my circuit:
simulate this circuit – Schematic created using CircuitLab
When the switch is closed it will short the circuit ...
0
votes
0answers
43 views
DC Block after the Balance - what problems would that cause?
I am building a radio receiver using the MAX2021 down converter. And I am building a down-conversion circuit similar to the reference design provided by the data sheet:
My problem is that I only have ...
0
votes
2answers
47 views
Volume Control - Logarithmic Potentiometer Placement
Thanks in advance!
I am building an headphone amplifier with PCM1794A, OPA1612, and OPA1622.
Where would be the best placement of the logarithmic potentiometer for volume control without decreasing ...
-2
votes
1answer
71 views
Difference between simulator and my analysis
I have this circuit:
I have done circuit analysis and found the total current to be 21mA.
Here is what I have done:
But when I run the same circuit in multisim it shows me 20.6mA.What could it be?Am ...
1
vote
3answers
116 views
BJT Common Emitter Output Resistance
Hello, I am attempting to determine the small signal output resistance \$R_o = v_x / i_x\$ of the Darlington pair common emitter's small signal model.
I have written the equation KCL at node c,
\$ i_x ...
0
votes
3answers
95 views
Convert square pulse with 24-volt amplitude to square 5-volt amplitude
Can anyone help me to make a circuit to Convert square pulse with 24-volt amplitude and has an variable offset voltage to square 5-volt amplitude and offset = 0 ?
I need to take a 24-volt amplitude ...
-1
votes
0answers
48 views
Balanced slope detector load impedance
Hello question about FM demodulation here:In a balanced slope detector in class we discussed this picture:
How can we connect a load to the output of the Balanced Slope Detector such that it doesn't ...
-1
votes
0answers
66 views
Mixed Multiplexer channels [closed]
I have a very unusual problem that i cannot even think what is causing it.
I have a circuit to read the resistance of a resistor. It produces a square pulse, that is analogous to the resistance.
This ...
0
votes
1answer
42 views
What is the equivalent capacitive load seen by the IC if in a datasheet of a chip CLmax=10nF given and I connect an RC filter as a load?
I have a stupid question where in the quick, the answer does not come into my mind.
If in a datasheet of an integrated circuit, a maximum load capacitance is given, e.g. 10nF, and I want to connect an ...
0
votes
1answer
25 views
Choosing the shunt resistor value and capacitor for op-amp integrator based on input resistance and DC gain
I think it's option C based on C = 1/R and the R2 as 10 times R1 but apparently the answer is option A.
Please tell me where i'm going wrong.
The full question reads
The following figure shows opamp-...
