4
votes
Accepted
High pass filter after TIA is not behaving as expected in LTspice
The NE5532 isn't good for these types of low-offset output voltage applications. There are several pointers in data data sheet: -
Input offset voltage
At your maximum gain (set by R169) of about 20, ...
- 443k
4
votes
6th-order filter simulation
To K Ket: Yes, I think you have selected a good design strategy.
1.)
The unity-gain S&K stages have (a) good high-frequency properties (from the opamp point of view) and (b) a good active ...
- 25.7k
3
votes
Accepted
Problem with PoE implementation and newer switches
A class class 1-3 PD need to draw a minimum of 10mA in order to ensure that the PSE doesn't disconnect, according to the standard. In my experience Netgear PoE switches behave quite "loosely"...
- 66
3
votes
How to filter a noisy PWM signal without affecting rise and fall times
What filter would you recommended to clean this signal without affecting the rise and fall times
Mathematically, it's impossible to do this with a linear filter, as a sharp edge has an infinite ...
- 90.3k
2
votes
UC3842-Based Boost Converter I made is not working. (Many beginner questions)
Your under-voltage lockout can be as high as 17.5 V for the UC3842. Rather use the the UC3843 that is aimed at lower voltage applications.
Below is a working design (many in the field) that can ...
- 201
2
votes
Accepted
Analog voltage signal threshold to latch output
Is there just a particular type of "flip-flop" circuit that I have overlooked that does this task?
Yes, the flip=flop you want is a toggle flip-flop, aka T-FF. The circuit you found is ...
- 1,522
2
votes
DIY Voltage and current regulator
FWIW, here's the circuit in the video:
simulate this circuit – Schematic created using CircuitLab
This circuit is not a "regulator" in any sense of the word. It is a simple emitter-...
- 170k
2
votes
Analog signal change detection
The easiest solution, by far, is a microcontroller with one ADC. Here's the kind of software you'd need to write (python-like pseudocode):
...
- 28.8k
2
votes
Accepted
Significance of higher noise gain of op-amp for AC applications
Yes, that is essentially the reason. This technique tricks the op amp into responding to a higher noise gain with regard to stability thereby improving stability margins.
If you were to ground Vin and ...
- 481
2
votes
Current Monitor output equation
op-amp both inputs have the same voltage.
V(R2) = V(R1)
Therefore current in R2 is some multiple of current in R1
...
- 32.5k
2
votes
Accepted
What's the transfer function of this op-amp circuit?
I tried to do my best to explain my concern. English is not my native
language so please be patient with me.
From a comment under the question: -
my question is more about the method
Break the link ...
- 443k
2
votes
Accepted
Audio Power Amplifier Layout clarifications
No. Differential impedance is unimportant at audio frequency. Actually this is switching so there will likely be signal at gigher frequencies, maybe 100kHz or so, but still - you don't need to worry ...
- 6,604
2
votes
Audio Power Amplifier Layout clarifications
Audio amplifier does not need characteristic impedance traces. The wavelength is about three orders of magnitude longer than any PCB trace would care about.
Yes, ampacity around an ampere will ...
- 27k
2
votes
Accepted
What is meant by active and passive in the context of transistors in ICs (Gray/Hurst)?
A MOS transistor (a PMOS, generally) can be used as an on-chip weak pull-up (This is quite a common approach that can be seen in today's MCUs). So the transistor here is used as a passive device.
An ...
- 30.2k
2
votes
Problems with choosing resistors for a common emitter - voltage divider bias amplifier circuit
You can pretty much determine collector current from the power requirement and the supply voltage. So, 0.2 watts divided by 15 volts = 13.333 mA so, broadly assume the collector current is 10 mA. That ...
- 443k
2
votes
Accepted
Problems with choosing resistors for a common emitter - voltage divider bias amplifier circuit
There's nothing wrong with your calculations and approach.
The issue is with the design because of a relatively low voltage gain without any emitter degeneration. If we were talking about higher (e.g. ...
- 30.2k
2
votes
Accepted
Balanced vs differential signals
This is my view of the problem
According to the electromagnetic theory of guided TEM waves: the current flowing at the surface of the central conductor and that at the inner surface of the shielding ...
- 783
2
votes
Balanced vs differential signals
Here are some equivalent circuits you may find illustrative:
simulate this circuit – Schematic created using CircuitLab
Consider for sake of argument, the values of impedances don't matter, ...
- 27k
2
votes
Why does the offset voltage have this polarity?
The polarity as drawn does not really matter, it's just there as notation for calculations to keep track of the signs.
For any amplifier, the offset voltage required to bring output differential to ...
- 136k
1
vote
Accepted
What is the direct coupling problem which differential amplifiers help avert?
Because a decently designed differential amplifier will have very little (or near-zero) common-mode gain (irrespective of a high differential gain), you can attach the differential outputs from one ...
- 443k
1
vote
Accepted
Do we need to guard the input traces of an audio power amplifier?
Do we need to provide guarding for +IN and -IN on the PCB layout?
No, if you were worried about high frequency getting into the input terminals then it would be better to place a high frequency cap ...
- 77.9k
1
vote
How to filter a noisy PWM signal without affecting rise and fall times
What filter would you recommended to clean this signal without affecting the rise and fall times of the PWM (such as a LPF would do)?
Do you simply need to measure the frequency and duty ratio of the ...
- 20.7k
1
vote
How to filter a noisy PWM signal without affecting rise and fall times
You should be able to filter out the high frequency component fairly easily, since it's an order of magnitude higher than your signal of interest.
Your signal is 88Hz, maybe up a couple hundred if you ...
- 6,603
1
vote
How can I read analog video signal from fpv camera by Raspberry Pi?
I'm not an RPi wiz, but I don't think an RPi is fast enough for real-time video signal processing. The NTSC composite video signal bandwidth is 4.2 MHz. The most common A/D sample frequency is 10.73 ...
- 18k
1
vote
How can I amplify an analog DC voltage signal?
Subtract 0.6V and scale by 9 and add 1V.
Or in math terms:
VOut = (VIn - 0.6V)x9 + 1V-> Vout [1;10]V with Vin [0,6;1,6]V
Or in circuit terms:
simulate this circuit – Schematic created using ...
- 3,026
1
vote
Analog signal change detection
Here's a quick and dirty proposal:
First the input signal is lowpass filtered by R1/C1 and buffered by opamp X4. Feel free to add more active filtering using the opamp. The output of this filter is ...
- 71.9k
1
vote
Analog voltage signal threshold to latch output
The system must be aware of its own current state, holding it until a trigger signal arrives to change that state. The "holding", as you have discovered, can be performed with a bistable ...
- 28.8k
1
vote
Analog voltage signal threshold to latch output
You could use an SR (set/reset)-flipflop and configure it to work as a T (toggle)-flipflop as in the following picture. You would need a seperate CLK for driving this.
Avoiding IC implementation could ...
- 6,759
1
vote
Peak voltmeter detector explanation
The feedback circuit create a precision half wave rectifier, a small amount of filtering, perhaps some compensation for the diodes, and as you say a voltage peak storage on C7. For reference here is a ...
- 9,109
1
vote
Which op-amp should I use to measure voltage across a current sense resistor?
I came across a similar question.
That's what I realized:
The operational amplifier can be with a different type of power supply: unipolar (for example: +12V and ground) or bipolar (for example: +5V ...
- 11
Only top scored, non community-wiki answers of a minimum length are eligible