Questions tagged [ne555]

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Voltage controlled 555 bistable operation

[Updated with working schematic!!!] I have a circuit which I tried to adapt from the 555 bistable configuration to have the 555 states controlled by input A and B; B always goes high before A. I am ...
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-1 votes
0 answers
83 views

Control pin 5 of NE555 for "softstart"

How can I control pin 5 of the "NE555" to ensure a soft start? I tried an electrolytic capacitor but it has no effect in simulation. I want the PWM to start gradually to the normal value, ...
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-1 votes
4 answers
86 views

NE555 stable frequency vs duty cycle change

I am experimenting with NE555 trying to get it to output stable frequency as duty cycle is changed. Circuit is powered with a 9V DC supply. The schematic is attached. The R3 is here so that the charge ...
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2 votes
4 answers
180 views

What is the relation between NE555 voltage doubler output voltage vs load?

Considering this circuit (NE555 voltage doubler), how can I find the formula for the relation between the value of the load resistor and the output voltage? You can see below two examples of this ...
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0 answers
92 views

555 timer emits tone regardless of reset value

I made a microcontroller circuit on a PCB and I attached a typical timer circuit to it. The IC of the timer is an 8-pin DIP texas instruments NE555 Resistors are 5% tolerance. Output capacitor is ...
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3 votes
1 answer
244 views

High voltage +170V based on NE555 design - short circuit

I love Nixie tubes so I decided to build a Nixie clock. I am a beginner. I have one successful design that electronics SE helped me design. That PCB was based on through-hole components and an Arduino....
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  • 121
1 vote
4 answers
173 views

Pulse a 555 astable oscillator every second without an additional IC

I am developing a ranging device to help people with blindness. I need to pulse a 38 kHz Infrared LED every 1 second. A 555 timer in astable mode generates the 38 kHz modulation. I'm currently using ...
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0 votes
1 answer
79 views

Sequential LED turn signal

I am trying to build a 4 LED sequential turn signal using the ne555 timer module and some comparators. I am having trouble with my next steps when trying to figure out what is wrong with my design. ...
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0 votes
1 answer
77 views

Single shot delay timer using the TI NE555 IC

I am trying the implement the following circuit that was simulated on Falstad. I tried implementing it using the TI NE555 timer IC but it does not work like the one in the simulation. I want the ...
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  • 101
1 vote
1 answer
110 views

MOSFET increase voltage on load is too slow

Can someone help me correct turn on N-MOSFET transistor (M1)? I want control Load using MOSFET with start delay. The delay based on RC with discharge. As a load use Monostable NE555: When the ...
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0 votes
0 answers
89 views

Dual 555 siren circuit keeps burning 555 ICs, but why?

I've found the following circuit online, which creates a siren sound from two 555 ICs. Please note: the 1ohm resistors were added because Falstad otherwise assumes that a capacitor without resistor ...
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  • 13
0 votes
1 answer
76 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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0 votes
1 answer
38 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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0 votes
3 answers
102 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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0 votes
1 answer
95 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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1 vote
1 answer
97 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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2 votes
2 answers
198 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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0 votes
1 answer
92 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 ...
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1 vote
0 answers
244 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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0 answers
63 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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  • 207
0 votes
2 answers
98 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 ...
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2 votes
1 answer
291 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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3 votes
2 answers
272 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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0 votes
1 answer
3k 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/...
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4 votes
1 answer
229 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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  • 81
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1 answer
151 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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  • 1
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0 answers
114 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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0 votes
2 answers
48 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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0 votes
2 answers
156 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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1 vote
2 answers
210 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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0 votes
1 answer
62 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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0 votes
0 answers
168 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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0 votes
0 answers
27 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 ...
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3 votes
1 answer
248 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 ...
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4 votes
1 answer
282 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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0 votes
0 answers
54 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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0 votes
0 answers
80 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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2 votes
3 answers
1k 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 ...
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4 votes
3 answers
307 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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0 votes
2 answers
203 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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0 votes
3 answers
122 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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0 votes
1 answer
64 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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0 votes
3 answers
222 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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0 votes
0 answers
94 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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0 votes
1 answer
892 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 ...
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0 votes
1 answer
61 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 ...
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0 votes
1 answer
82 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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0 votes
2 answers
103 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 ...
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4 votes
3 answers
632 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 ...
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  • 41
2 votes
2 answers
295 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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