# Questions tagged [analog]

Analog circuits have a range of voltages, rather than just two as in digital logic.

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### 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
2answers
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### 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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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?...
1answer
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### 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, ...
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 ...
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 ...
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 ...
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 ...
1answer
108 views

3answers
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### 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. ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
0answers
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### 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 ...
1answer
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### 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 ...
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-...