# Questions tagged [analog]

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

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### Wien bridge oscillates at 6x expected freq and amplitude oscillates too

A while ago I made a Wien bridge oscillator to go from ~500 Hz to ~1 MHz, using an NE5532 opamp and stabilizing amplitude with the typical opposing diodes method. Worked fine, but the output was too ...
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### Audio amplifier setup is triggering headset button detection [closed]

I have a laptop I swapped in with an existing desk setup that includes a mixer for the audio from several computers an amplifier that I use to split the microphone from my headset between all the ...
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1 vote
108 views

### How can the power of an oscillator be calculated?

I am designing a hartley oscillator and would like to know how much power it consumes. How can I figure out how much power the hartley oscillator consumes mathematically? edit: I meant mathematically ...
1 vote
60 views

### What is the proper way to make a configurable split-supply voltage clamp with voltage dividers?

Being a beginner in electronics and not having had exposure to a lot of “best practices” I was trying to generalize the voltage clamp to arbitrary positive and negative clamping voltages. The ...
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### Clock feedthrough of the bootstrapped switch

I'm learning about the bootstrapped switch through this paper. Razavi used a 20 µm / 28 nm NMOS (M1) as the main switch to achieve low Ron. I am wondering does this wide device cause any problem ...
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1 vote
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### Why does this two stage op-amp not work?

I was trying to simulate a two stage op-amp I had just learned about. I am going step by step i.e. as you can see from the schematic I have started with ideal current sources. I know that this op-amp ...
42 views

### How does analog IC benefit from channel length shrinking?

I have some experience in OTA design for both 180 nm and 130 nm technologies. I didn't see much advantage of using 130 nm, as I had to use quite long channel length to achieve an acceptable gain in ...
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42 views

### Why the loop bandwidth must be much smaller than the input frequency to ensure settling behavior?

Razavi said, in Section 9.6 Loop bandwidth of his book RF Microelectronics that In the design of PLLs, we impose... a loop bandwidth much smaller than the input frequency to ensure a well-behaved ...
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### NE567 supply voltage

The below image lists supply voltages for NE series ICs: Figure 1: supply voltage Why is the IC supply voltage given as absolute positive voltage (some in thelist specify +/- values) rather than a ...
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### Implementation of Circuit in AN104 for Load Transient Test

I have been testing the transient response of line regulator simply with a MOS and the resistor, this method, however, cannot generate arbitrary current and the current is not accurate. To improve the ...
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1 vote
69 views

### Amplification Calculation

I have a question about how to calculate the amplification of amplifier. Here is the circuit: The equation provided by in the datasheet for calculating the output is: CURphase = VOFS - amplification *...
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### Level shifter (floating shifting ?)

I'm currently studying level shifters, and I have a question: Is it possible to design a level shifter that translates 0 and 5 volts to VSS (e.g., VSS = 5V) and VDD (e.g., VDD = 8V)? If so, could you ...
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22 views

### How to stimulate PSRR of LT3060-2.5 and LT1761-2.5 in LTspice?

I tried following the steps on the analog devices website but it seems that with these components the results are not close to the datasheet while when I try this method with others it works. Do you ...
107 views

### Opamp dual package IC configuration

I have a question regarding the configuration of opamps for sensor signal amplification. I have a circuit with two sensors going through identical signal conditioning circuits (amplification and ...
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### Why are my results different from their PSRR scheme?

Even though I followed every step given in the Analog devices website, the results were still different and I don't know why. Can anyone give me a solution? Here is my result: But their PSRR ...
92 views

### Why isn't this inverter based amplifier amplifying?

I was studying about CMOS inverter an amplifier for analog applications instead of its more well known application as a switch for digital circuits. For the following inverter based circuit : I think ...
118 views

### Is my solution to this differential receiver circuit calculation correct?

I solved the difference receiver circuit problem in the picture with the following formula but I am not sure of its correctness because I do not have an answer key. I would like to discuss whether it ...
106 views

### Why does the author assume $R_{in} = 1/ g_m$ for this this circuit?

The following circuit is from Chapter 13 of Analog Design Essentials, page 1324, written by Willy Sansen. Calculate $R_{in}$ for this circuit. The author thinks $R_{in} = 1 / g_m$ However,  -...
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### Audio amplifier for school project

For a school project, we have to explain this design of a audio amplifier. We have only been able to understand to parts marked with colored rectangles. The design comes from the book audio power ...
40 views

### Change analogWrite() frequency using the arduino framework for SAMD51

I am using Adafruit Feather M4 Express board which has Atmel SAMD51 controller on it. I am using platformio as IDE, which lets me use this controller using the Arduino framework. I want to change the ...
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### How is the $M^2$ term derived in the PLL output phase noise spectrum?

Originally, I was interested in the derivation of Equation 12.5 in the RF synthesis chapter of Razavi's textbook Design of phase-locked loops. I tried to look up the origin of it and found out a very ...
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1 vote
149 views

### Supercapacitor discharging fast when there is no discharge path present

This question is a continuation of my previous question, but different from that. I am using a PCA85073A RTC in my design. On some boards, the supercapacitor discharges very fast (5 V to 1.1 V in half ...
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76 views

### What will happen if I2C pull up voltage became zero

This is a continuation of this question. In my board RTC I2C lines are pulled up to controller supply voltage and the controller supply voltage will be off when the system is off. At that time also ...
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70 views

### I want to combine four analog inputs into one output using two op amps. Is this feasible?

I'm doing my first project with electronics and I'm trying to figure out how to make an Arduino read input from four identical sensors using one analog pin. I'm using multiplexers on my other sensors, ...
80 views

### Photodiode Signal Temporal Broadening Below Saturation

I'm a physics PhD student working on a project to use silicon photodiodes for detection of longwave infrared (6-10um) ultrashort pulses. (Specifically doing higher-order autocorrelation) Despite ...
40 views

### DC Offset of a single-ended OTA

I'm confused by the concept of DC offset voltage. According to this application note by TI, DC offset seems to be the result of the asymmetry (Vth, bias current, etc.) - they only consider the '...
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### Make a female to female SCART PCB

I recently bought an off-brand female-to-female SCART coupler but I wasn't happy with the quality of the image. I thought it could be better to just make one myself with a simple PCB that links each ...
39 views

### Offset of a comparator

I'm confused about the offset of the comparator. Consider a comparator consisting of a pre-amp and an inverter. Does the offset come from the misalignment of the preamplifier's Vocm and the threshold ...
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57 views

### Switch Protection

I am using SPDT and multiplexer switches in my design and these switches are directly connected to Px connectors for various channels. Transducers (capacitive load below 500 Ω) are connected at Pin 2 ...
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### How is the gain of this CS stage (gmRo)^2 in this oscillator?

I was reading this paper which uses MEMS active mode resonant fin transistors for making a mmWave Oscillator. I came upon this schematic for the proposed oscillator in the paper, which says that the ...
131 views

### Average filter of a signal in C

I'm having troubles designing a code for an ADC measurement, I'm trying to read a signal that comes from charging a battery with pulses, so the signal will be something like the photo uploaded. ...
123 views

### Pulse generation from a constant current source

I need to generate a biphasic pulse as shown below. [![enter image description here][1]][1] The specifications of the pulse is given below. Amplitude 0~10mA Pulse width 10~500µs Constant inter-pulse ...
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1 vote
63 views

### Is my understanding about the ECG waveform is correct or not

I need to design an amplifier for an ECG signal.The signal specification is given below. BW = 0.47Hz..40Hz (-3dB) – Limited by the system Signal amplitude max. 10mVPV (peak-to-valley), DC offset max ±...
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656 views

### 74LS161 miscounting

Following Ben Eater's 8-bit computer assembly, my program counter, which is built out of 74LS161s, does not count correctly. In trying to figure out the issue, I have completely isolated the circuit ...
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### Why does a class A amplifier stop amplifying at high frequencies?

Below is a simple Class A amplifier. Why does it stop amplifying at very high frequencies? Why does it distort so much? Here is the output by frequency: It rises, as predicted, but only to about 2 ...
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244 views

### How to analyze common-emitter amplifier by reflecting base impedance to emitter?

In chapter 2 of Dr. Middlebrook's video series Technical Therapy for Analog Circuit Designers he gives 2 examples of how solving a CE amplifier by "doing the algebra on the circuit diagram" ...
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### TLP292 Schematic Review

I am designing a circuit with TLP292. Below is the schematic. The I/P is coming from a microcontroller it is either 0 V or 5 V. The output current is 15mA to 20mA May I know is this circuit is fine? ...
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47 views

### How to use a monostable 555 one shot circuit with a single dc rise at the trigger

In order to measure battery contact fidelity/degradation I am developing a "one shot" current measurement circuit. Basically, when a HV battery is plugged into a connector I will have a ...
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53 views

### BFU730F doesn't work on real experiment, what is wrong?

I have calculated BFU730F transistor on paper - all is ok. I have created simulation for similar transistor (BFR740 because there is no BFR730) - all is ok. I have maked shematics - it is not working. ...
1 vote
71 views

### In a class A amplifier using a (BJT voltage divider bias) with no transformer coupling, how can one calculate the input DC current? [closed]

In a class A amplifier (using a BJT voltage divider bias) with no transformer coupling, how can one calculate the input DC current? The current drawn from the supply is ICQ (which flows in the ...
77 views

### Distortion in a negative channel of the differential amplifier THS4505

I designed a single-ended to differential signal amplifier using a tool provided by Texas Instruments: The source signal passes through a voltage follower (OPA810IDBVR), so the output resistance ...
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### measuring NI 9215 for measuring pressure using pressure transducer

I need to measure pressure using pressure transducer with output of 0-10 V & 0-10000 psi range and NI 9215. How could be the code?
46 views

### Designing a D-FF in Virtuoso to create 90 degrees phase shift

I am currently trying to design a digital circuit in Cadence to produce a 90 degrees phase shift to a CLK signal within my current circuit. Below is an image of a D-FF setup as well as the output ...
53 views

### differential gain for mismatched $g_m$ in differential amplifiers

I couldn't understand how the author came up with the expression of differential mode gain. He states to look from the Fig 4.17 to derive this expression, whereas the fig 4.17 has no mention of \\$R_{...
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### Square law conversion analog circuit using log and antilog amplifier

My approach to performing a circuit that could square root the input is to use a combination of log amplifier > inverting amplifier > exponential amplifier > inverting amplifier. The 2nd ...
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### Root Extractor circuit

I'm currently building a root extractor circuit in LTspice following this schematic provided in the link given below but instead using ADTL084 opamp: https://usermanual.wiki/Document/snla140b....
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1 vote
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### Should I use CD74HCT4067 as 16:1 analog multiplexer or design my own multiplexer using Mosfets?

I was thinking to design an 16:1 analog multiplexer using transmission gate and and gate based decoder circuit. But I was advised to use CD74HCT4067 instead as our design is an off-chip design. I am ...
52 views

### Generate 200MHz Phase-Shifted Voltage Sine Waves

I'm looking into a way to construct a circuit that can generate ~200MHz negative voltage sine waves (8 channels), where there is 11 degrees of phase offset between the channels (0 deg, 11 deg, 22 deg, ...
56 views

### How to change the gain for this amplifier?

I'm modifying a hot-chassis TV to add a Y/C input. To isolate the inputs, I'm using an optocoupler with the following circuit: The jungle IC, however, requires a 4.5Vpp signal on the chroma line: Is ...
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