Questions tagged [analog]

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

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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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\...
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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.
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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 ...
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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
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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 ...
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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 ...
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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 ...
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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 (\...
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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 ...
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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 ...
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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 ...
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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,...
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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 [...
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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 ...
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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 ...
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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 ...
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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 ...
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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
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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 ...
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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
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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 ...
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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
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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 ...
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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
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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 ...
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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?
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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 ...
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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
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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 ...
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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?
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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
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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
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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
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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 ...
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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
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...

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