For questions about preventing the flow of DC and very low frequencies while passing AC signals.
For questions about preventing the flow of DC and very low frequencies while passing AC signals.
Questions tagged [dc-blocking]
11 questions
5
votes
4 answers
What is the purpose of this extra capacitor in this opamp low pass filter?
I'm trying to follow along with this blog post reverse engineering the HC-SR04 ultrasonic distance sensor.
The signal from the receiving transducer is amplified, filtered, and then amplified again.
On the filter, there is a 1 nF cap C4 between the…
user364952
- 151
- 1
2
votes
1 answer
RIN measurements of a laser
I want to measure the relative intensity noise between 0 and 1 MHz of a laser using a photodiode (20 MHz BW), a voltage amplifier (10 MHz BW), and a spectrum analyzer. Since I don't have so much knowledge about electronics, I would like to clarify…
user302220
- 21
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1
vote
1 answer
Importance of DC blocking capacitor type when we don't care about audio quality
I am working on a board design which is very limited in space. I am taking input from a passive guitar pickup and sending it through a high impedance buffer op-amp, a low pass filter, and then a non-inverting op-amp. The final output is a cleaned…
J.P.
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1
vote
1 answer
My values for this DC block and level shifter, part of an amplifier, are incorrect. I must be missing a key concept
I am trying to find the correct component values for a leg of an amplifier. There will be non-inverting amplifiers attached to From_First_Stage_Out and To_Second_Stage_In. This part of the circuits needs to:
block the DC offset from the first op…
corgiworld
- 143
- 5
1
vote
1 answer
LTspice DC-blocking capacitor not working
I have been busy with a frequency shift keying modulation circuit in LTspice. The modulator works but I have this horrible DC-offset! I have tried high-pass filters and DC-blocking capacitors but I cannot get it to work correctly. Can someone point…
N. Berg
- 159
- 11
1
vote
1 answer
How to choose a blocking capacitor for RF power amplifier
I'm using a power amplifier that requires an external blocking capacitor for the input and output ports and I'm trying to decide the best value to use. My understanding of this is that I choose a capacitance that is sufficiently large such that the…
MattHusz
- 1,033
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1
vote
1 answer
DC block capacitor choosing with 50 Ohms input impedance
I need block DC in a 50 Ohms terninated system. The passband will go from 100Hz to 100MHz, so the needed capacitance is around hundreds of uFs. For normal chip capacitors, I think I must take the ESL into consideration.
Are there any good methods…
diverger
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0
votes
2 answers
Advice on simulating amplifier and power splitter circuit in LTspice
I am using LTspice to simulate an AC resonant circuit that should amplify and split an RF signal. I would like to add small circuit to it, so that it should add a DC offset to the original circuit.
How can I simulate this circuit where I can see…
Nana
- 11
- 1
0
votes
2 answers
Series capacitor not blocking DC voltage
In my understanding a series capacitor (with some resistance) works as a DC block, essentially forming a high-pass filter, blocking DC. Under this assumption, a unipolar square wave of amplitude V passed through a series C and resistor would result…
MPA95
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0
votes
1 answer
DC blocking cap
When is a DC blocking cap needed and when not?
In my case I have a two stage audio amp:
simulate this circuit – Schematic created using CircuitLab
I read that is a good habit to have them on input (1), because you cannot be sure about the signal in…
Status Re
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0
votes
3 answers
LTSpice DC Block capacitor
I saw some other questions here about DC Block capacitors in LTspice and none of them helped me with my problem.
The question is very simple, why we have a DC offset when using capacitors as DC block in LTspice (even with a parallel resistor)?
The…
astable
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