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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 ...
Simon Mayr's user avatar
1 vote
2 answers
58 views

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 ...
balu's user avatar
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0 votes
1 answer
144 views

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 ...
JSK's user avatar
  • 35
0 votes
2 answers
265 views

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. ...
Jean's user avatar
  • 19
1 vote
1 answer
145 views

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 ...
JSK's user avatar
  • 35
1 vote
1 answer
74 views

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 ...
Michal Podmanický's user avatar
5 votes
2 answers
179 views

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 ...
Evg's user avatar
  • 51
2 votes
5 answers
475 views

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-...
Optik's user avatar
  • 23
0 votes
2 answers
326 views

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 ...
Sam Gallagher's user avatar
1 vote
0 answers
78 views

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 ...
BarryTheLad's user avatar
2 votes
2 answers
258 views

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 ...
Erik Vincent's user avatar
3 votes
3 answers
204 views

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 ...
Aaron Butkovich's user avatar
3 votes
3 answers
255 views

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,...
user1728582's user avatar
4 votes
2 answers
147 views

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 ...
Frank's user avatar
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0 answers
51 views

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 ...
Michal Podmanický's user avatar
1 vote
1 answer
157 views

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 ...
benjamin_ee's user avatar
0 votes
0 answers
79 views

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 ...
lurscher's user avatar
  • 139
0 votes
1 answer
149 views

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 ...
slazien's user avatar
0 votes
1 answer
59 views

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 ...
Tim Flahvin's user avatar
0 votes
1 answer
41 views

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?
O-Negative's user avatar
0 votes
1 answer
176 views

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 ...
Bhargav Rajyaguru's user avatar
0 votes
0 answers
95 views

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....
ankyxia06's user avatar
0 votes
1 answer
82 views

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 ...
Feynman137's user avatar
  • 1,253
3 votes
3 answers
169 views

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. ...
user18926955's user avatar
0 votes
0 answers
107 views

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 ...
ankyxia06's user avatar
3 votes
3 answers
236 views

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 ...
ankyxia06's user avatar
0 votes
0 answers
55 views

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, ...
Luis Medina's user avatar
2 votes
2 answers
557 views

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 ...
Trever Thompson's user avatar
0 votes
1 answer
718 views

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'...
Oidipous_REXX's user avatar
1 vote
2 answers
215 views

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 ...
Ukpa Uchechi's user avatar
0 votes
2 answers
145 views

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 ...
user488476's user avatar
1 vote
1 answer
292 views

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. ...
FUZxxl's user avatar
  • 500
0 votes
1 answer
210 views

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 ...
Baba Yaga's user avatar
3 votes
4 answers
828 views

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 ...
denizyildiz70's user avatar
1 vote
5 answers
713 views

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 ...
Charlie's user avatar
  • 71
1 vote
2 answers
560 views

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, ...
Serg's user avatar
  • 111
0 votes
1 answer
213 views

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 ...
rs04's user avatar
  • 57
0 votes
3 answers
287 views

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 ...
rs04's user avatar
  • 57
0 votes
1 answer
374 views

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 ...
kecske3141593's user avatar
4 votes
4 answers
1k views

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 ...
Bastien's user avatar
  • 144
2 votes
2 answers
476 views

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 ...
CDW's user avatar
  • 21
-3 votes
1 answer
387 views

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 ...
Abd Alhaleem Bakkor's user avatar
0 votes
1 answer
218 views

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 ...
ScienceDiscoverer's user avatar
0 votes
1 answer
155 views

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 ...
Some nerd who does not have a 's user avatar
0 votes
1 answer
129 views

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 ...
Pixel Brush's user avatar
2 votes
3 answers
1k views

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 ...
GNZ's user avatar
  • 1,759
1 vote
2 answers
327 views

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 ...
electrovolt's user avatar
0 votes
1 answer
194 views

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 ...
playingaround's user avatar
0 votes
0 answers
47 views

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 ...
electrovolt's user avatar
0 votes
2 answers
553 views

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 ...
Abhinav Tahlani's user avatar