Questions tagged [multivibrator]
The multivibrator tag has no usage guidance.
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What is the effect of V+ given from bottom in this multivibrator?
In the astable multi vibrator, the second figure has a V+ voltage given additionally.
What is the output of that circuit digram compared to first figure?
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How can I incorporate an LDR in a 555 flasher circuit? [closed]
I have designed this flasher circuit using a 555. I want to incorporate a light dependent resistor (LDR) to start flashing the LEDs only when it is dark. I can't figure out where I should put the LDR ...
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CD4098 as an astable multivibrator
I have a bunch of unused CD4098 ICs available and I was hoping to use them in DIY-project to drive a counter (therefore duty cycle % does not matter) in astable multivibrator mode with adjustable ...
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Why is this circuit not triggered (astable multivibrator) although it can be triggered on a breadboard?
Why is this astable multivibrator circuit getting balanced in a flash and not oscillating? It works on a breadboard. It once worked fine in simulation, but one day it stopped oscillating in simulation....
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Optimizing RC values on monostable multivibrator accounting for retrigger timing
I am attempting to use a retriggerable monostable multivibrator datasheet to tell me if an engine is on or off. The input to the IC is a square wave usually between 100-200Hz 0-3.3V. The signal is ...
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Why does output become inverted in op-amp astable multivibrator?
This is the circuit I'm considering.
I understand how Vo becomes Vsat, and Vn increases until it is equal to Vp, which is R1/(R1+R2)·Vsat.
Many people say when Vn slightly exceeds Vp, Vo is inverted.
...
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Which complementary astable multivibrator is more reliable to produce for tests on a breadboard?
Astable multivibrator coupled with complementary astable multivibrator:
I tried to build this schematic on a breadboard, but the complementary astable multivibrator circuit on the right does not work ...
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Complementary astable multivibrator vibration/oscillation reason
I set up this astable multivibrator on a breadboard. Sometimes it works and flashes on and off it, and sometimes it does not flash on and off - the LED stays on.
Is there any reason or specific ...
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Issue with a circuit in Multisim V14.0
I have a part of this circuit on a PCB working with a frequency of 1 Hz (I tested it with an oscilloscope; it works perfectly).
I have to change it to 2 Hz, so I tried to do that in Multisim V14.0, ...
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Op-amp triangular wave DC offset
I want to generate a triangular wave that has no negative component using op-amps. The method I am employing to generate the wave form is described here, and can be seen in this image:
As in the ...
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What's the use of the capacitor before the speaker here?
I'm new to electronics and trying to get a grasp of the basics at the moment.
For this purpose, I'm reading the book Make: Electronics by Charles Pratt (in a German translation.)
In one experiment, he'...
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Is my understanding on flip flops accurate?
I have done a lot of research on flip flops so to speak and I have put together my understanding, please correct were I’m wrong.
Flip flops are bistable multivibrators able to store two states (one ...
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Astable multivibrator small capacitor values
Is there a method to determine the values for the resistances? below shows when R1=R2 << R2=R3 and the capacitance is 10uF and the circuit works perfectly.
However if I try to reduce the ...
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How can I build a current controlled 50% duty cycle oscillator from two CMOS inverters?
I am in need of a current controlled audio range (output around 1000 Hz) oscillator/multivibrator circuit. To make the result sound nice, I want to oscillator to have a 50% or near 50% duty cycle. ...
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What happens if we give a negative trigger pulse before a monostable multivibrator reaches it's stable state
Monostable Multivibrator using Op Amp, from this link,
Obviously there is a certain amount of time that the capacitor takes to charge again from -Vcc*β to VD (0.7v) and therefore during this period a ...
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Low amplitude output in Opamp square wave generator
I have made a square wave generator using an OPamp in positive feedback.
The generator was designed to output a frequency of above 200KHz, so I chose the values of 200ohm and 0.01uF for the RC circuit ...
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CD4047 only has OCS output when operated in astable mode
I'm trying to build a simple astable multivibrator using a CD4047. I try to demonstrate using 3 LEDs on the OSC, Q, and Q` pins. Following is the circuit I built (copied diagram):
The only difference ...
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Newb trying to understand astable multivibrator
I've been trying to understand one thing about the astable multivibrator below. According to https://www.build-electronic-circuits.com/astable-multivibrator/, at the very beginning of the operation, ...
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Astable multivibrator frequency mismatch
I made an astable multivibrator using an NE555p and a transistor. I checked the frequency and found it to be 220 kHz, but it should be 481 kHz.
I used a resistor of 1 kΩ for both R1 and R2. The ...
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Why does the astable multivibrator using transistor not work when I use the same value of resistance for the collector of both the transistors?
The circuit shown in the figure does not run even in proteus. But when I change the collector resistance above 1.43k of one of the transistor, the circuit starts working. What's the reason behind such ...
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I made an astable multivibrator, connected it to a transformer, and I really don't know what's going on
I tried to drive some H-bridges with the multivibrator circuit to drive a small 1:25 SMD transformer to make hv for geiger tubes. My results were slightly underwhelming, so I started to do random ...
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BJT astable multivibrator frequency increasing with voltage
I'm trying to get a 27V 120Hz square-wave, so I tried this circuit :
I get a decent 128Hz signal with 9V, which is close enough. However, if I increase the input voltage past a certain point, the ...
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PNP Astable Multivibrator Variation
I am trying to learn astable multivibrator circuits and I found one in an EL wire driver.
I have noticed it has a 100nF ceramic capacitor connected between the transistor bases and additional 22R ...
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precise 50 Hz oscillator [closed]
I need an astable multi-vibrator at exactly 50 or 100 Hz with exactly 50% duty cycle.
using circuits like 555 can't give me that with the common well-known values of components R and C , let alone the ...
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Why is my Multivib piezo atomizer/transducer driver not working?
I'm tying to drive a "Moisturizing Transducer Mist Maker Atomizer Film Plate" using a simple astable multivibrator circuit like this:
I can't make it work. No reaction from the atomizer. I ...
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BJT twin transistor astable multivibrator always outputs high
Noob here (again). I have made this schematic of an astable multivibrator and a Raspberry Pi. I want it to produce a square wave, but it just outputs high constantly.
I use the Raspberry Pi as a ...
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Astable Multivibrator using BC549s not oscillating
I just recently started learning about electrical engineering stuff, and since my final goal of building a Z80 Computer seems a bit far away, for now, I decided I'd make a simple clock I could ...
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How to skip the first pulse triggering for this circuit?
Following my previous question, I came up with the following circuit using 74HC123 for simulation and in practice planning to use this IC. The circuit out should be ON when it waits for a rising edge ...
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Astable multivibrator malfunctioning on circuit board
Here is the circuit that I've built on my project board (GL-12)
Here is a schematic:
Note: I'm using BC107B transistors instead of BC547 as they are quite similar.
To test the circuit, I added two ...
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Using a DSO138 digital oscilloscope to probe a circuit
I'm new to using a DSO138 to probe my circuit.
In order to get the square waveform on my DSO for an astable multivibrator, do I need to connect a jumper wire from the collector of a transistor of the ...
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Figuring out the importance of components in a circuit-2
This is a follow-up question for this qs which I asked earlier
Here is the full specifications-
The simulation gives me a current of 6.5 mA through D1 and 833 micro-A through D2. Also, I get the ...
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How to actually calculate the rise time for a square wave generated by an Astable Multivibrator?
If I have an astable multivibrator like the one shown in the picture, how do I actually calculate the rise time for the output square wave? I know that it's the time required to change from the low ...
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What actually causes the distortion in the output wave due to an Astable Multivibrator?
I've witnessed that the output square wave from an astable multivibrator using two BJTs has its edges rounded during the rise up time(just as it is seen in fig. 1). Across resources, I've come to know ...
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Connecting a RC circuit to the output channel of an astable multivibrator (follow up question)
This is a question which I had asked earlier.
Tinkering around, I found out that if I connect a capacitor to the load resistor, i.e. if I pass the output through a RC circuit, the voltage retains it ...
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Playing around with an astable multivibrator
I had a doubt regarding the astable multivibrators using BJTs.
This is a typical astable multivibrator.
I have been told that if I connect a capacitor to the output channel, there would be no ...
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Astable multivibrator not producing a square output wave, using two BJTs
I've been trying to build an astable multivibrator circuit using two BC547B NPN transistors.
I know how to build one using a 555 timer, but I'm having some problems using transistors.
I should've ...
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Window comparator with transient detection
I need some advice with over range circuitry I my design. In summary, I need to probe two nodes in my circuit and raise an alarm if any of them raises above approx. 2V peak (in both polarities). The ...
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PVT indepedent CMOS multi-vibrator design
I am doing a process, voltage, temperature (PVT) analysis of an RC-based multi-vibrator. Simulations under varying temperature (0-100 C) and process corners (FF, FS, SF, SS) show signal delay in the ...
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Unstable astable multivibrator
I'm trying to do an ngspice simulation of a 1KHz astable multi-vibrator.
While I can achieve oscillations the output is very erratic and all over the place. [edit: two good responses below who said ...
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How to read a schematic with capacitors
I've tried many times to read electronic schematics. I always struggle to understand how to read it in order to understand how the circuit works.
The most important problem I have is trying to figure ...
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What is wrong with my circuit and how can I fix it?
This circuit used to work before I soldered it. When I initially soldered it, I used a 6V battery and it was oscillating, but the speaker was very quiet. I went with a 9V battery and I re-soldered ...
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I don't understand the working principle of this metal detector circuit?
The circuit below is a metal detector circuit. The inductor serves as a "sensor" to detect metal. The tone of the speaker changes when a metal is detected. However, I don't know anything ...
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How do I make an edge triggered T flip flop using integrated injection logic (I2L)?
I have been searching everywhere online on how to make this circuit. I found out I can make NAND gates using I2L and connect them together to make a T flip flop , but this is very impractical since I ...
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Why is the input trigger pulse in a monostable multivibrator fed to the base of the transistors through a capacitor and not an inductor or resistor?
In a monostable multivibrator, one of the transistors will be fed with a trigger pulse using a capacitor. I have heard about capacitor coupled circuits like stagger tuned amplifier where one single ...
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In an astable multivibrator, why doesn't negative feedback prevent the output from ever saturating?
What I understand of an astable multivibrator so far is this:
The output saturates to one of two extremes, which drives the capacitor in the negative feedback loop to either charge or discharge.
Once ...
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Very high current frequency on transistor collector
simulate this circuit – Schematic created using CircuitLab
I am designing astable multivibrator for homework and I have calculated values for resistors and capacitors (hopefully right) but I ...
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Astable multivibrator using op amps - why does it start?
I'm new to electronics and I'm learning some circuits with op amps. Now I have been shown this astable multivibrator.
I understand how it works.
The op amp is saturated at one side or the other
...
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Current direction in a multivibrator
I have been studying multivibrators lately, but I have hit a wall right now. I have attached a sketch for an astable multivibrator. I know the basic stuff. When Vout is high then Vin will rise as CT1 ...
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Analysis of a multivibrator circuit
I have trouble understanding the operation of the following circuit:
This is the given description of the schematic:
"This is a voltage controlled multivibrator that is used as an acoustic volt ...
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How to build an arbitrary (one-shot) pulse generator?
I need a circuit/IC that can generate a single pulse with a variable pulse width (I would want a minimum of 50 ns but if that is not possible the next minimum can be 1 μs, and even if that is not ...
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