Questions tagged [analog]
Analog circuits have a range of voltages, rather than just two as in digital logic.
2,617
questions
3
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2answers
217 views
Feedback in multistage amplifier
I found this schematic online for an audio amplifier and I noticed the 100k was some sort of feedback system between the base of the first stage and the emitter of the next. How would you describe ...
1
vote
0answers
58 views
What is the purpose of a diode in parallel with a BJT in a MOSFET drive circuit?
This circuit shows a complementary emitter follower driving an IRF 150 MOSFET. The textbook says that a diode D provides a path for the discharge of the base-emitter junction capacitance of transistor ...
4
votes
2answers
612 views
Why do differential signals need an inverse wave?
At the moment, I'm working on converting a single ended audio signal to a differential one (source is a CS42L55, need a differential input for a CSR8670. The latter's datasheet is indecisive about how ...
0
votes
1answer
50 views
Could impedance mismatch explain my distorted signal?
I have a custom PCB which scales and offsets an analogue signal, using an instrumentation op-amp (INA114). When I use a scope to look at the output, it looks distorted (see images below). When I use a ...
0
votes
0answers
72 views
100mA current sensing circuit limiter
Please i need your help. I am to design this circuit to be able to produce an 100mA at the output as i reduce the load resistor from 1k to 0Ohm. I am having problem on how to go about it for my ...
1
vote
3answers
62 views
Amplification in multistage amplifiers
I'm building a double stage Common Emitter preamp and I'm wondering about the order of amplification. I want a voltage gain of 30 coming out of the second stage; would it matter if I had x10 in the ...
1
vote
2answers
54 views
When does separating digital and analog ground make sense, is it essential, and when is it not? Should I separate the grounds in this project?
I created a simple sequencer design based on several digital chips. The circuit is powered by a simple 7805 voltage regulator. When designing the board, I separated the analog ground of the power ...
0
votes
2answers
51 views
Reverse engineer VFD control signal from schematic
There's a TLDR at the bottom!
I got a brushless DC motor and VFD from an old treadmill, both are Baldor brand. Unfortunately it looks like they were made by Baldor specifically for this treadmill, and ...
2
votes
2answers
74 views
Group delay changed?
I'm cracking my head at this problem, right now. It is the continuation of the work that I'm doing with this: Relation between group delay, pole frequency and quality factor.
So, as I said this is a ...
5
votes
3answers
588 views
2.4V Zener diode regulator not clamping
I am trying to get a toggleable 2.0 to 2.6 ish voltage reference that can supply up to 45 mA.
I simulated the below circuit and found this to be acceptable. However upon building the circuit, I found ...
1
vote
1answer
59 views
Relation between group delay, pole frequency and quality factor
So I'm solving some problems on filters and came up with an apparent contradiction that I would like to get clear.
Considering a low-pass biquadratic section:
$$T(s)=\frac{V_o(s)}{V_i(s)}=\frac{K_0\...
0
votes
1answer
65 views
Is this question wrong? possible to calculate gain without beta or Ic given?
How to proceed with this question? I can't think from where to start.
0
votes
1answer
48 views
Using digital and analog signals in the same cable
I am working on a project with 3 PCB : PCB1 is the master, it communicates with two slaves, PCB2 and PCB3.
PCB1 is powered by a battery and it redirects the supply to PCB2 and PCB3. Each PCB includes ...
0
votes
0answers
31 views
IR LED Diming using PWM [closed]
I want to make an IR-led dimming circuit that will control by PWM what changes should I make in this circuit... It shouldn't operate above 5V (low power) and should not use current when it's not in ...
1
vote
1answer
50 views
Probabilistic Analog to Digital Convertion
I was listening to a talk where the speaker mentioned a couple of ways to represent an analog signal with a digital signal. He mentioned the typical ones like:
Encoding the analog value in terms of ...
1
vote
1answer
52 views
How to make a passive linear circuit to generate high voltage spikes from 10V peaktopeak square wave with a source res. of 50Ω, with f less than 5MHz
How to implement a passive linear cırcuıt to generate high voltage spikes from 10 volt peak to peak square wave with a source resistance of 50Ω with some f (freq) less than 5MHz.
Peak value, Vp, of ...
3
votes
1answer
186 views
Help figuring out an op amp circuit with two loudspeaker outputs
I have to design a circuit that amplifies a sine wave with either a AD8616 or a LTC6256 (currently using the AD8616) to a 50 ohm loudspeaker and a rated power of 0.5 W. I'm a novice when it comes to ...
0
votes
1answer
44 views
Thevenin Equivalent of Common-Gate Amplifier
I'm having some difficulty understanding how Razavi determined \$V_{\text{in, eq}}\$. My understanding was that the small-signal model allows us to model the PMOS device as a constant current source (\...
0
votes
1answer
47 views
Can I measure analog voltages for a circuit with multiple power supplies?
I have two components in a circuit: An Arduino Uno R3 and a Wind Sensor Rev. P. See diagram below. The wind sensor requires 12V to operate, so I powered it with an external power supply (provides 12V ...
0
votes
0answers
47 views
Radio - Amplifier Connection
This is my first post here, so please give me feedback on how I can improve in the future.
Background
I am trying to reverse engineer a Becker Grand Prix Stereo Radio with an external amplifier.
On ...
0
votes
4answers
117 views
Problem with drawing vector lines on an XY oscilloscope, caused by X and Y being set at slightly different times
I'm doing a project where I need to draw shapes on an oscilloscope by controlling the X and Y channels from a microcontroller, to eventually make a game which you can play on your oscilloscope.
I've ...
0
votes
0answers
35 views
Photoresistor audio switch on battery power
I'm trying to build a light-driven chime silencer for a wall clock. The schematic from https://electronics.stackexchange.com/a/177401/18259 seem like a very good starting design for this:
It, however,...
0
votes
0answers
33 views
Chopper FET as a Preamp
I have a small kit whose schematic is here, it has an LM386 (or equivalent) with an FET preamp stage.
The FET went bad, and in searching for a replacement for the now obsolete part, I found that the [...
0
votes
0answers
62 views
LM311 overheating
I breadboarded the circuited below. Within seconds of operation, both the L7805 and LM311 start to overheat very badly.
I tought it had something to do with the coupling capacitor or the AC signal so ...
0
votes
1answer
34 views
Inverting a (voltage-) transfer function using opamp
If we have a circuit that - given some input voltage \$U\$ - produces an output voltage \$f(U)\$ (where \$f\$ is continuous, monotonic descending), we can construct a new circuit that behaves like the ...
0
votes
0answers
19 views
What is the equation for “beff”, i.e., “Gain Factor in Saturation” in BSIM4?
Using the device parameter list in Cadence, I found out that ID follows this equation exactly:
ID = 1/2 * beff * vgt**2
I also found out that ...
0
votes
1answer
41 views
Maximum signal transmission from OPAMP output
I generate an analog voltage from PIC microcontroller output. I want to transmit this analog signal to maximum distance as much as possible using single wire. I have non-inverting OPAMP at the output ...
0
votes
2answers
90 views
Designing mil-std-1553 transceiver [closed]
I need to design a mil-std-1553 analog front end transceiver to already designed digital 1553 ip for my ms thesis. So I need to convert digital 3.3V to analog specs level and receive and convert to ...
0
votes
1answer
36 views
Using analog comparators to get 2 different outputs depending on the input
I am trying to use analog comparators to get two different output voltages, 6V out when the input voltage is -8.5V <= Vin <= -2V and -3V out when the input voltage is -2V < Vin <= 9.5V. I ...
0
votes
0answers
26 views
Designing differerntial Sigal modulator
I would like your suggestion on my first design Differential signal modulator [simulation attached].
Before jumping into design let me highlight my objective. I am differentiating a control signal of ...
0
votes
2answers
76 views
How can Gilbert Cell circuit provide linear gain variation even though ID-gm relationship is nonlinear?
How can Gilbert Cell circuit provide linear gain variation even though ID-gm relationship is nonlinear?
As I undertstand it, the vcontrol (the voltage at the gate of M5 and M6) changes the biasing ...
3
votes
3answers
469 views
Analog input scaling before ADC sampling
I'm trying to read a voltage value from a chemical sensor. the sensor value can range from 0 to 7 volts. My microcontroller is running on 3.3V. I'm not allowed to consume current from the sensor so I ...
2
votes
0answers
64 views
Would it be worthwhile to replace this OpAmp by a discrete amplifier? [closed]
We have a circuit which works correctly with an OpAmp (as shown below) but we are considering replacing it with a discrete amplifier.
The gain we need is about 2200. The input signal comes from a ...
1
vote
0answers
97 views
LM2576 simulation not working at datasheet frequency
I'm designing a buck converter with TI's LM2576. This is the functional block diagram of the IC, extracted from the the official datasheet
Output node voltage will be a square wave, and inductor ...
1
vote
1answer
116 views
Analog input to ATMEGA328P using op-amp - how does this circuit work?
I was looking for a good solution in order to use a bunch of components and read 0-10V/0-20mA and digital inputs using my Arduino Pro Mini (ATMEGA328P working at 3.3V.)
I've found online this ...
1
vote
1answer
63 views
Regarding Miller compensation
Can anybody briefly explain about Miller compensation?
What is the need of pole splitting?
How does it improve both the unity gain bandwidth and phase margin?
0
votes
1answer
41 views
alternative values of these resistor in circuit?
i am working on a spectrum analyzer, concept is to feed audio signal to esp32 and perform FFT at 40000hz sampling rate. I tried MIC input but did not get satisfied by results.
link to diagram
I found ...
0
votes
0answers
38 views
Common-Source Stage with Diode-Connected Load
I have a question about the small-signal gain in a common-source stage with diode connected load.
I understand there are multiple equations for gm and the one you use depends on what relationship you ...
0
votes
3answers
49 views
Analog linear interpolation of AC signals
I have two AC signals in audio range \$V_1\$ and \$V_2\$, both around \$2\,\mathrm{V}\$ p.p.. I need to interpolate between the two linearly through some external control voltage \$V_c\$ (ideally also ...
-1
votes
2answers
37 views
Cascode MOSFET Vds
Hi, I am having some difficulty understanding the statement underlined. How does M2 see Vb-Vth2 across its drain source?
0
votes
1answer
93 views
ESP32 grilled with simple MOSFET switch for 12V water pump
I've soldered a small PCB around an ESP32 with following components:
ESP32 Dev v4
Water pump with 12-24V and 4.5-6W rating
Power supply with 12V and 1A rating
Capacitive sensor with analog output
...
0
votes
1answer
56 views
Need transistor circuit to supply pulse/gnd signals to optical switch
I am a digital designer so anything analog is out of my expertise. I need to control an optical 2x2 switch with the following truth table:
The pulse is in the msec range and the driver current is ...
0
votes
1answer
43 views
Audio amplifier bridge tied load (BTL) output as analog signal to MCU
I am trying to find a way to amplify the signal from an electret microphone & feed it as an analog signal to a microprocessor to drive LEDs based on sound. If I look at the amplifier ICs they all ...
0
votes
1answer
24 views
Unexpected output of op-amp in Proteus
When I try to simulate a circuit I designed in Proteus, I'm getting an unexpected output from the op-amp.
As you can see from the image, for op-amp U1:A, the inverting terminal voltage is about 3.25V ...
0
votes
2answers
52 views
Multi-Stage Common-Source Amplifier - When is it no longer a small-signal?
I have a question about the actual definition of a small-signal signal. We use it all the times in amplifiers. But how small is a small-signal? When does it stop becoming a small-signal?
Take for ...
3
votes
3answers
298 views
Trouble understanding output impedance of common collector
I'm self-studying electronics. I'm currently following "The Art of Electronics" (p. 84, 2.2.5 Emitter follower biasing), helping myself with additional videos and tutorials as I go.
I'm ...
0
votes
2answers
77 views
Making a light detector using a phototransistor and an open drain comparator
I want to make a light detector using a phototransistor. To do that I connected a phototransistor and apotentiometer to the open drain comparator as in the diagram below.
When the light is dim, ...
0
votes
0answers
36 views
BJT common collector Hartley Oscillator
This question is specifically about the BJT Common Collector Hartley Oscillator. In the corresponding Colpitts oscillator the feedback fraction is equal to C1+C2/C1 where C1 is the capacitor with ends ...
-1
votes
0answers
21 views
Can channel-length modulation coefficient be larger than 1?
Channel-length modulation coefficient lambda is ideally zero or desired to be as small as possible in real case. I haven't come across the case where lambda > 1. But if Ids is very much sensitive ...
0
votes
0answers
40 views
Sinking and sourcing switching I/O hardware configuration
This is the Siemens S7 PLC and I'm wondering what's the internal circuit of the I/O looks like?
I'm trying to design an I/O circuit that allows me to switch between sinking and sourcing I/O by ...
