Questions tagged [multivibrator]
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172
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Astable multivibrator, potentialy bad circuit
I found this circuit scheme in my examples, and i think that this circuit wont work.
Aside protection diodes of CMOS inverters, there is this diode pointing in the first inverter(left one), how I ...
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Unexpected Behavior in Transistor-Coupled Astable Multivibrator Output
I tried to build an astable multivibrator to periodically run a vibration motor. I coupled the motor to the oscillator via a BJT. The circuit is:
The expected collector voltage of Q3 is:
To test the ...
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Calculating capacitor charging and discharge time using LM311 as Schmitt trigger astable multivibrator
I need a little help solving some electronics problem. I need to calculate the charging and discharging time of a capacitor in the following Schmitt trigger astable circuit using LM311 I found. If I ...
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Most energy efficient way to make a LED blink using a multivibrator [duplicate]
I'm using this LED. I want to make this LED blink at MAX brightness (100 mA) at 1 Hz. I need to use a multivibrator and therefore can't use any IC chips. The circuit is powered by a 3.7V battery with ...
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Role of the load resistors in an astable multivibrator
I am currently trying to wrap my head around astable multivibrators. I want to design a circuit that oscilates at about 1 kHz. The formula I am using to determine the values for the base resistors (I ...
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Timed momentary switch modifier
I would like to design a circuit that adds a power off delay
What would you suggest, is it possible to solve that basing only on the circuits batteries? Modifier from the market uses own 9V power ...
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333
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CD14538 and MC14538 are advertised as interchangeable, but one works on my board and the other doesn't
I am repairing a board that originally uses MC14538 (dual monostable multivibrator) ICs. Since these are obsolete, I planned to use CD14538s, whose datasheet claims that the two are interchangeable.
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Analysis of NAND-based low-power monostable circuit
I've seen a monostable multivibrator circuit shown below. The purpose of the circuit is to provide a power to a circuit for an amount of time controlled by potentiometer after pressing the momentary ...
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Modified astable multivibrator with sharp edges
I am designing an astable multivibrator that would avoid rounded output edges and also has a totem pole output, so it is able to drive a small charge pump.
So I decided to replace a collector ...
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What is this extra diode (LED) between the bases of transistors in an astable multivibrator?
Can someone explain what this extra LED between the bases of the transistors in an astable multivibrator does?
I built the prototype and I see that without this LED there is no blinking. Both sides of ...
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How does a capacitor in an astable multivibrator turn off a BJT?
I've recently started learning about astable multivibrators. I understand that the capacitors in a circuit like the one below create the alternating current by charging up one at a time, and once they ...
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Why does the frequency of an astable multivibrator depend strongly on the supply voltage?
More specifically, my question is why does the natural frequency of the canonical (basic) symmetric transistor astable multivibrator (STAM) vary so strongly on the power supply voltage? As a follow-...
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How does this BJT monostable one-shot work?
This circuit comes from Hamilton's Handbook of Linear Integrated Electronics for Research, 1977, p. 240. It is similar to the common BJT monostable multivibrator, but it doesn't include the feedback ...
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Struggling with the design for a simple logic circuit [closed]
I'm working on a circuit that would store 4 bits and flash them on an LED. These would be stored on a 4 bit register, and should be outputted when a button is pressed. My goals is to take my 4 outputs ...
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555 Timer Astable Multivibrator Circuit Analysis
I was looking at a dead Molex "Suitcase" terminal applicators and found on its controller board this 555 circuit. It appears to be an astable multivibrator, but not the typical kind.
It ...
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Is there any such thing as a tristable, quadristable, etc. multivibrator?
The title says it all.
Is there a discrete circuit that can produce 4 different outputs based on a single tactile switch click?
I'd like to do this with either a discrete design or a 74373 since ...
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Control timing of Monostable Multivibrator
Im having a hard time really understanding a Monostable Multivibrator.
What I'm trying to achieve is being able to control the timing of the vibrator with a microcontroller of some kind. (arduino, pic,...
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555 astable resistor location
When looking at example schematics of a 555 astable circuit, they all show the two resistors in series with the C. I'm wondering how this differs from the schematic I've created below;
Here R6 is ...
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Astable multivibrator and latch in one
I am trying to design a combined function of oscillator and latch in one circuit to spare parts.
Seems it is working but anyway do you think it is OK or did you see somewhere this circuit?:
simulate ...
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Square, Triangular and Sinusoidal Wave Generator with AmpOp and Diodes
I'm having trouble building a circuit to generate square, triangular, and sine waves. In theory (calculations), everything is correct, and in the simulation (done in LTSpice) everything is also ...
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Optimize a design for current/charge oscillator
I'm trying to understand how to design a circuit that cycles charges between two capacitors between cycles. Basically I want a large positive current pulse into one cap at the same time a large ...
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Astable multivibrator 555 circuit not working
I'm a beginner in electronics. I'm trying to follow the below schematic for building an astable 555 circuit. Based on the resistance set on the trimmer potentiometer, the speaker should make sounds of ...
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Unequal timing of alternating LEDs in a multivibtrator [closed]
I have built a basic astable multivibrator from the Electronics for Dummies book.
The LEDs alternate for sure but one lights for a much longer time than the other.
I would have expected this if the ...
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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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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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