Questions tagged [astable]
The astable tag has no usage guidance.
120
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Measuring capacitance with NE555 in astable mode
I have one problem with my project. I trying to measure capacitance with NE555, but i have problem with protection.
In this schemeatic instead of a capacitor, I have put connection socket 01x02 for ...
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7
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Regulating output of 555 astable oscillator [duplicate]
I need to build a circuit that takes a 12v DC input and produces a 5v DC 30Hz square wave.
My thinking is to produce the square wave using a 555 in an astable oscillator configuration, and then step ...
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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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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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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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Astable multivibrator GaN MOS
I'm a beginner in electronics design. I'm trying to build on LTSpice an astable multivibrator using the GaN transistors GS-065-030-2-L 650 V E-mode. The idea is to obtain an oscillating output of 24 V,...
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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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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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555 timer is unstable for a few seconds after power application
I have built the circuit from this answer.
I have R1 = 10k and C1 = 6.8nF which seems to be giving me about 7.5kHz output.
The timer works just fine but from a cold startup, the output is wildly ...
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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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288
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Power transformer circuit using H-bridge doesn't work as expected
I am trying to step up my AA battery's voltage (which is 8 volts in total) using an ignition coil (which is rated for 12 volts input.)
To drive the coil I am using an H-bridge at a frequency of 50 kHz ...
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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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5
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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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555 Astable : Separate charge and discharge resistors?
The 555 astable oscillator seems to be usually implemented with one common resistor between the charging and discharging paths of the capacitor.
Is there something wrong with putting one resistor for ...
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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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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 does the output of my astable multivibrator using an op-amp turn into a triangular wave?
I've designed an astable multivibrator for square wave generation using the LM741 op-amp, as showen in the following image:
Now I've played a little with the frequencies it can output. As shown in ...
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267
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How to limit the output voltage of an op-amp astable multivibrator
I'm trying to make a square wave generator with an adjustable range of output signal amplitude (between 0 and 5V) using an LM741 op-amp and the following circuit:
The thing is, VOUT is limited by the ...
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3
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275
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555 Astable output staying high
I have a ICM7555 with a 12 V supply in an astable circuit. When ENABLE goes high, I want my output to be high for a given amount of time, then carry on as a normal astable from there.
So I have a ...
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How to set the initial conditions of an astable multivibrator
Consider the following oscillator circuit:
I have this running and oscillating at about the frequency I want. However, when first powering it on, one of two things happen:
Both LEDs momentarily ...
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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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347
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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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370
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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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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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4
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Would using the output of a 555 timer to charge/discharge its capacitor work?
Background
I'm relatively new to electronics and playing around with a 555 timer.
I found that for astable operation, all sources I've seen recommends the following design (with different resistor and ...
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Astable 555 circuit always on, not oscillating
It has been quite a while since I've used a breadboard or looked at circuits (probably 20+ years since high school and college physics.)
I'd like to think I know how they work, but something isn't ...
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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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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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Toggling between astable and monostable input to dual 555 timer pulse generator
Hi there,
I am looking to build a simple analog circuit to generate adjustable pulses for a medical device. The current circuit utilises 2x LMC555 timers - one in an astable configuration to generate ...
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852
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555 timer to measure variable capacitance
I've no experience with complicated circuits. Currently thinking about a simple circuit for detecting a variable capacitance, e.g for liquid level or moisture sensing. I came across the 555 timer ...
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555 timer Theremin - capacitor choice, and question about mixing signals
I'm trying to create 555-timer based Theremin, but I have a few questions that I don't quite understand. For now, I'm building it on a breadboard (yes, I know it's not the best option), but I don't ...
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NE555 - astable flashing alternative LED circuit
NE 555 help - astable alternate flashing LED circuit
"In the circuit, the LED1 lights when the output pin has a HIGH state and LED2 lights when the output is in a LOW state." - I couldn't ...
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What would be the main advantages of constructing an astable multivibrator with two CMOS inverters?
What would be the main advantages of constructing an astable multivibrator with two
CMOS inverters? Can these semiconductor
devices be declared to introduce small parasitic capacitances to the circuit?...
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Circuit question for LM358 and NE555
I have made an IR proximity sensor which works fine when an LED is connected.
Figure 1: This is the IR receiver and emitter part of the circuit. The white LED is connected to ground via a 270 ohm ...
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Astable multivibrator: what starts the first cycle
I think I understand how the astable multivibrator works once the LEDs are blinking (cf. below), but I don't understand how the first cycle begins.
I can see that at first, the 2 LEDs are on (based ...
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555 Timer Astable Mode
Just to clear things up. This is NOT a homework question, but it is lecture notes used as a practice exam.
I am trying to understand the 555 timer in oscillation (Astable) mode particularly the ...
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I'd like to know whether my attempt to increase duty cycle will work
I've been looking for a solution to make an astable multivibrator give me a 90% duty cycle or a duty cycle above 50%. This is what I came up with. I have very limited resources and means of testing, ...
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I've built dead bug (on steroids) boost converter
I know it looks sloppy but this is my very own homemade boost converter! It outputs 6watts of power from a 3.7v battery(phone battery)...
It's switched by an astable multivibrator, and the switch is ...
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2
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970
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Bypass capacitor in 555ic
What will happen if we don't bypass capacitor at pin 5 of 555 ic as an astable multivibrator.Will voltage/current changes in line affect on pulse width?will capacitor at pin 1 discharge late?
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How does a boost converter power the oscillating circuit and load at the same time?
so I've put together a boost converter circuit of my own and I have a problem, I want my boost converter to output reasonably high current but whenever I connect a high current load - the astable ...
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How does this astable multivibrator circuit with FETs work?
I am having trouble understanding this schematic. I do understand that it is pretty simple, but I just can't seem to get my head around part of it.
The schematic is a more complicated version of an ...
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CMOS astable circuit
I have made the following astable circuit in Multisim:
However, it didn't work (oscilloscope reads 0V as an output.)
I think the problem is because of VDD and GND pins which are hidden in Multisim.
...
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Feedback on astable 555 timer circuit to control MAC valve for turbo control
I have some questions and wanted to get feedback on this circuit I have put together. Basically to see if there is something I missed or obvious that I should change or should have designed ...
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Two questions about astable multivibrators and transformers
Here's something that confuses me: The output on an astable multivibrator will be shown on a multimeter as half the input voltage (for example we have 9V-0V-9V-0V...and the multimeter averages it out ...
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Gating an astable 555 output signal in a way that oscilation always starts with a Low to High transition
simply, the circuit is a 38KHz signal generator for an IR remote project. the output signal should be gated by an MCU according to IR timing intervals recorded earlier. the design with the 4148 diode ...
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Astable 555 circuit not oscillating
I'm a complete beginner to electronics, but I'm trying to follow Ben Eaters video series "Building an 8-bit computer". I tried to do the first part of an astable 555 timer, but the LED does not ...
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