Questions tagged [ne555]

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1answer
51 views

Is this variable resistor not connected to ground?

I want to build the following PWM fan controller circuit: I am not sure about the connection of potentiometer. Usually one of the terminals is connected to the supply voltage and the other is ...
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1answer
30 views

Varying duty cycle of an square signal using comparator

Recently i've been tinkering with the interrupter of my solid state tesla coil and the circuit that utilizes two ne555 timer ic,one in astable mode and another one modulating via pin 5 of the first ...
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3answers
79 views

Restarting a 555 timer

I recently came into ownership of a (sort of) arcade machine and I'm looking for a little help to figure out if it's possible to modify it. Long story short, the coin-op uses a simple circuit composed ...
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1answer
63 views

Can't make simple oscillator based on NE555

I apologize for a very stupid question, I'm very beginner in electronics. I wanted to make a simple oscillator based on NE555P chips I ordered from local store, but struggling to make it work. I found ...
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1answer
60 views

Are 555 PWM circuit resistor and capacitor values independent of the voltage applied to a 555?

I am new to electronics so my question sound dumb. I am using this diagram to build a 555 timer IC PWM circuit: The above circuit operates on 9V but I have 5V. Do I need to change capacitor and ...
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2answers
142 views

How to get a single pulse for 10 milliseconds?

I am trying to get a single pulse of 10 milliseconds on the output of my 555 timer. I following is my schematic: I am supplying 12 V for Vcc. The value of Resistor R and capacitor C is 100 ohms and ...
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1answer
40 views

PWM regulated by a LDR , the darker it is outside, the darker are the LEDs

I'm doing a hobby project with an electronic panel. The panel is going to have some white LEDs under switches names. Since im going to use the panel at all times of the day I want the LEDs to be ...
1
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0answers
107 views

How does the 555-timer AM radio work?

The 555-timer is used here as a demodulator. I don't understand how the 555-timer generates the desired signal. Shouldn't the output have the same frequency as the carrier signal? Can someone please ...
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0answers
57 views

Why are Switching Signals Used for DC-AC converter

I have noticed that oftentimes an NE555 timer circuit is used to generate AC switching signals, which allow a DC to AC rectifier to convert a DC voltage to AC voltage. This AC voltage can be used for ...
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2answers
70 views

Change LED blinking frequency depending on voltage

I'd like to make an LED blink with a varying frequency that depends on a voltage. I know about the 555's control pin, but I'd like the blinking to vary continuously, instead of switching between just ...
2
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1answer
213 views

Dual control an output with a MCU's GPIO and a capacitive touch button (TTP223)

I am a newbie in this electronic world and English is not my first language, please be sorry for any inconvenience I may create. It was a long story for me to come up with this writing, let get a bit ...
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2answers
131 views

How to turn a Latch circuit from Press-ON/Press-OFF to Press-ON/Hold-OFF circuit and how to make it auto-off when power is first connected?

I'm building a Latching circuit using 555 IC. The schematic is as follows: The Input voltage is 12V and is used to operate the 555 IC that switches a relay coil through a transistor. When the circuit ...
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1answer
632 views

Why does the 555 timer have a maximum frequency of 2MHz?

according to the website, the 555 timer has a maximum frequency of 2MHz. Why is it not less or more? What property of the timer makes the limit of the frequency? Website:http://groups.ist.utl.pt/lee/...
4
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1answer
134 views

What space applications use the 555 timer? [closed]

The 555 timer is considered the most famous integrated circuit of all time and is also credited with a versatile use in space travel. Hans R. Camenzind (the designer of the 555 timer) said that this ...
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1answer
90 views

Combining CMOS and TTL with drivers and Leds with relay driver

I need some practical advice on how to combine different component types. I designed a circuit with at the heart an up/down counter (74f269) The outputs of the counter are connect to via 330 ohm ...
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0answers
80 views

How does the comparator in the NE555 compare its two inputs?

This is a circuit diagram from the very detailed and helpful NE555 Wiki page. The yellow and red coloured segments are comparators, comparing Thresh and Trig to fractions of Vcc. If I know how a ...
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2answers
34 views

Output voltage\current of 555

Im trying to understand what is the output voltage\current (pin 3) of that 555. If I get it right, when low (logic 0) AND Vcc is 5v AND output current is 8mA, the ...
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2answers
105 views

switching off 555 timer with trigger button

I am new to working on 555 timer. I am running it in monostable mode. I am triggering it using a button on trigger pin. It works just fine. What I want is the LED connected to the out pin 3 to switch ...
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2answers
91 views

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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1answer
57 views

My NE555 circuit triggers falsely when connected to the mains using a 5V adapter

I have designed a laser security system using an NE555 in monostable mode with a potentiometer to adjust the pulse length. Another NE555 (U2) ciruit is used for delaying power on the monostable ...
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0answers
100 views

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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0answers
23 views

NE555 delayed monostable timer with discharging capacitor after poweroff

I'm using the following circuit to try to simulate a button press in a speaker: This is supposed to wait 2 seconds, set the output high for ~500ms and then set it to low. The output of the ...
3
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1answer
191 views

Light bulb lights up in a fraction of time (blinks) using TRIAC-BT136 and MOC3021 (Solved)

I have several days with problems when assembling the circuit of the image (it is a light bulb that turns on when you clap). To briefly describe the operation of the circuit, when the potentiometer is ...
4
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1answer
216 views

555 startup timing issue

I'm new here, as I'm slowly drifting from mechanics and programming into more electronics stuff. The question I have, is if anyone could possibly point me in the right direction, as all of my searches ...
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0answers
43 views

What is equation for the 555 timer control voltage in monostable

How do i get the 555 timer in monostable output frequency when there is voltage apply at control voltage. I only able to find the formula for astable which is Orignal post:- What is the equation for ...
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0answers
58 views

why the 555 timer output is not the same as my calculation

Hi may i ask why is my calculation for the 555 timer of U2 is not the same as the simulator. U1 output signal 22064.24Hz, 92.81% duty cycle. t=1.1* R_1*C_1 t=1.1* 10k* 2.2n t=1.1* 10k*2.2n t=0.0242ms ...
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3answers
974 views

555 timer - large inaccuracies with precision components [duplicate]

This is a problem I have been slowly chasing down. At first I was using 10% caps that caused the poor output accuracy. After changing the capacitor to a 1% I thought the problem would be fixed, but it ...
4
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3answers
239 views

How does the led fade circuit with the NE555 timer work?

I searched about this and each explanation did not make any sense,my explanation is that when the OUT pin is HIGH the transistor turns on and the capacitor charges,also the led turns on gradually ...
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2answers
105 views

How to bypass continuous input on Trigger pin of 555 IC after some time working in Mono-Stable/ One shot version?

I configured the 555 IC such that it gives the output pulse for 3 Seconds (Approx.) as soon as there is input on trigger pin, but my project requirement is; even if there is input continuously on ...
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3answers
99 views

555 trigger amplitude slightly too large to trigger

I have the following circuit which is designed to take a longer pulse (on the order of miliseconds) from a microcontroller (source v3 below) and use two 555 timers in cascade to output two consecutive ...
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1answer
57 views

AM circuit LTspice

I have to analyze the following circuit and understand its function. As far as I understand the top part is the simple phase-shift oscillator generating output sine wave at circa 145kHz. The NE555 is ...
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3answers
170 views

how to solve the phase shift of a ne555 timer

Why is the first pulse wave is not the same as the rest of the wave in this 555 timer? Is there any way to remove the wave before 2 ms or is there anyway to make it same as the rest in the graph.
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0answers
64 views

Schmitt trigger using NE555P gives wrong output

I am trying to create a Schmitt trigger using NE555P to generate square pulses from some periodically changing signals. I used the following circuit diagram and applied some sinusoidal waves (3.3v). ...
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1answer
585 views

Want to replace push-button with IR receiver

In the diagram below I want to replace that push-button switch Sw1 with IR receiver, I tried a lot with different combination with IR receiver and tried with transistor but I failed, so, please how ...
0
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1answer
46 views

Calculating resistor values for N3904 transistor

I'm using an N3904 as a not gate to trigger a 555. What resistors do I need? I don't know how to For R_I I want to: limit ...
0
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1answer
62 views

convert momentary switch to toggle switch using 555

this circuit diagram is used to convert a momentary switch to toggle function , how can i extend the diagram to get three output stats to switch between two LEDs and an off state if it possible
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2answers
100 views

Boost Converter Stuck at Around 80 Volts

I'm building a boost converter that utilizes a 555 timer switching at 60 kHz at a 96% duty cycle which drives an IRF3205 MOSFET to power a hand wound inductor (calculated to have ~330 uH) with a 6A10 ...
4
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3answers
456 views

Why can this ignition coil driver circuit not produce high voltage but only ~ 300 V?

Why is this ignition coil driver circuit not working correctly? (The coil is of this type, but used the model shown in the photo below.) The coil is driven with 16 V @ 5 A @ 540 Hz but I cannot get ...
2
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2answers
181 views

Resetting 555 via Transistor - RESET PIN LOW TOLERANCE

I have a circuit with a NE555DR timer that generates a pulse. The reset is held low and lifted when a voltage of 5 - 24V is applied to P0-3. A PNP transistor MMBT5401 that pulls pin 4 to ground when ...
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2answers
276 views

Trigger & Reset 555 same button

Been working on this for a while. Circuits are not my strong point. Power Source =5.5v dc The first image is a 4093 NAND that another used helped me with. It changes a dual led from one color to the ...
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2answers
133 views

NE555 in a light detecting circuit

I'm completely new to electronics but my degree gives me a basic course with a project at the end. I built this small circuit to detect when a light is shined on the LDR to turn on an LED so ...
20
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5answers
3k views

Is the NE555 the IC I need, and if not, what do I replace it with?

I've noticed that whilst I have a well-known solution using an NE555, that IC doesn't fulfill my needs perfectly. Others have told me that the NE555 is very rarely an appropriate solution to one of ...
1
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1answer
811 views

2-channel dimmer from NE555 + LM358?

I have a 12-24 V dimmer for LED strips like this: https://www.circuitlab.com/editor/#?id=c8m48y simulate this circuit – Schematic created using CircuitLab I want to understand a couple of ...
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2answers
220 views

Replacing an NE555 with a 74HC123D

I want to replace an NE555 with a 74HC123D in a battery powered device. It is used to clock a CD4017, for which I need a pulsed signal of 46Hz. I read that a 74HC123D needs less power than a 555. How ...
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3answers
2k views

555 timer frequency is way off

I'm currently designing a 555 timer to provide a 38kHz square wave to drive an IR LED as part of a beam interrupt detection system. This beam interrupt is a part of an embedded product where we ...
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4answers
161 views

Turning on LEDs [closed]

I started a small project where I want to have three LEDs which are turning on gradually (in first step just one is on, one second step two are shining and then all three). I've tried doing it via ...
5
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3answers
172 views

Why won't this 555 timer flashing circuit work?

The circuit which I made shows the following behavior, when power is given to the circuit: Sometimes it lights up, sometimes it doesn't. When it does light up, it flashes properly for a few seconds ...
1
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1answer
144 views

Need help in designing of circuitry. (Power Electronics)

The circuit is supposed to detect ambient light and react accordingly. When there is high illuminance the LED should be dim and when there is low illuminance the LED should be bright. The transistor ...
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0answers
193 views

Over current Protection for Ne555 circuit?

I made simple frequency generator circuit with Ne555 but almost in every circuit Ne555 IC burns after few use. Ne555 starting to heat up then outputs weird signals , if I don't stop the supply Ne555 ...
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3answers
107 views

How to connect LED to output device to show the output state without any voltage drop so that it can be sensed by MCU?

I am using an NE555 timer to get output from one of my output device. The basic function of NE555 timer here is to toggle the output of my output device which was successful but I need to attach a LED ...