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Questions tagged [ne555]

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3
votes
1answer
75 views

555 Astable Timer produces incorrect period/frequency

I am building a 555 astable timer circuit for a course which must match the BPM of a song. The song has a BPM of 104, which requires a timer frequency of roughly 1.733 Hz. The circuit looks as ...
0
votes
0answers
75 views

How does the capacitor charge and discharge in this configuration?

I wanted to build a metal detector using 555 timer and I found this circuit online along with a video of the working model. It says that the timer works in astable mode. But since the capacitor is not ...
0
votes
0answers
35 views

how to use more than one TSOP1837 sensor in one circuit? [duplicate]

How to use more than one TSOP1837 sensor to sense IR in different areas, for example one in front of car, another in back?. In other word I want to use multiple TSOP sensor in one circuit that uses ...
-1
votes
1answer
81 views

Doubt about a NE555 [closed]

I created this circuit a few days ago, but I'm a beginner in electronics, so I do not know if it's well done This circuit causes the LED to turn on after 5 seconds and to keep it on Could someone ...
0
votes
0answers
61 views

Safety of an Inverter Circuit

I built this circuit for an EL driver/inverter I found on this website: https://dcroy.blogspot.com/2011/02/ The transistor is a TIP122 Darlington transistor and I used this transformer in the circuit....
-3
votes
1answer
106 views

Astable 555 not oscillating [closed]

I've been struggling with building a 555 timer for a project. I get the expected voltage at pin 3 (output), but the problem is that it's not oscillating. The Vout is constantly 8.4V, while I expected ...
0
votes
2answers
142 views

Changing frequency of 555 timer with varicap or capacitor

I have created a 555 oscillator circuit where the output is set to have flashing LED light. Now I have a problem when I change the voltage of the potentiometer, the output frequency does not change. ...
0
votes
1answer
68 views

NE555 Circuit stops working after random time

i finished my NE555 circuit and created some pcbs. After a few attempts i could get the circuit working, and tested it successfully. I placed my circuit between a 12V 1.5Hz square wave signal and a ...
0
votes
1answer
71 views

Strange behaviour of ne555 + pmosfet circuit

I was a silent reader for a long time and could solve all the problems on my own, but this problem is really freaking me out. I was messing around until 3 AM today with this "feature" and still don't ...
0
votes
0answers
123 views

How to create a pulse using 555 when the push button is released (“dead man” switch)?

I want to make a "dead man" switch using 555, basically 555 will generate a pulse only when a push button is released (you push the button and nothing happens until it's released). Two days of ...
8
votes
5answers
1k views

What to make with hundreds of 555 chips [closed]

This is a little bit different question than normal.. Aliexpress is ruing my life, sometimes i order things i don't even need because it seems cool. A few time ago I ordered 500x 555 chips for just a ...
0
votes
0answers
48 views

Determine the frequency and on time of two coupled ne555

I've the following circuit: I use it as a voltage controlled pwm generator. My question is, how can I find the frequency and on time of the PWM. I tried changing all the resistor and capacitor values ...
0
votes
1answer
97 views

Is there anything wrong with this particular timer circuit utilizing 555?

I created following simple timer circuit for one shot operation. My expectation is it to give 5v as output (for D RELAY and SP RELAY) for certain number of seconds/minutes soon as it got powered-on. ...
1
vote
2answers
115 views

NE555 Controlled Transformer Voltage Spikes

I am attempting to build a NE555 timer controlled step up transformer (3:250). R2 and R3 will be variable resistors when it is completed. Input is 12V and I'm stepping that up to about 1000V. The ...
0
votes
1answer
232 views

Vibration sensor switch for Car

I am building a small GPS tracker for my car using a Raspberry PI Zero plus some additional components. I would like to keep it off unless the car is turned on or it's moved forcefully. To do that I ...
0
votes
3answers
251 views

Installed 555 timer socket backwards - can I reverse the chip in the socket?

I installed the socket for a NE555 timer ic backwards on a PCB. Can I just reverse the chip in the socket to cure the mistake?
0
votes
2answers
414 views

Repair help. Mosfet keep shorting

I have "repaired" a cnc power nad speed control board from yoocnc (china) and it worked fine for a day. the next day the spindle just started running as power was applied. the mosfet was shorted, the ...
1
vote
1answer
315 views

Very Basic 555 Timer oscillator not working

I've been trying to make an LED blink. My first approaches were without the 555 timer, and they were unsuccessful. I decided to make an Astable multivibrator circuit. I'm using an NE555, and I'm using ...
0
votes
1answer
81 views

555 - HIGH then long delay [duplicate]

I trying to create a circuit with only one 555 to send HIGH on output(3) for very short time, like 200ms, then set LOW for something like 20~30 seconds. Then I'm just need turn on circuit, then: a) ...
2
votes
3answers
2k views

Can I place a relay at the output pin of a 555-timer

I recently remember running across a bunch of articles on web about the 555-timer, it’s my first IC. I’m getting more familiar with it, and I want to know run it in a-stable mode, with a relay ...
8
votes
2answers
2k views

NE555 Based Speed Controller circuit - Contradicting Pins in 2 Tutorials

I am a newbie of Electronics and learning it as a hobby. Over a course of time I realized that Electronic Blogs are not the best place to learn Electronics, unless you have a strong basics and can ...
3
votes
1answer
149 views

How do I reset NE555 output to LOW when powered on?

Here is a functional NE555 push-on push-off switch. But the problem with this is whenever the power source is connected, it starts in random On or Off position. How to modify it so that it always ...
1
vote
2answers
331 views

Cannot Understand the 555 IC Reset

I have designed the schematic diagram of the inner components of the 555 Timer IC for understanding the working of the IC, but not sure if I have designed it correctly or not. If it is correct can ...
0
votes
2answers
1k views

independent control of frequency and duty cycle in 555 timer (formulas)

I want to control frequency and duty cycle of output pulse of 555 timer. I searched and find this schematic in a post in SOV but I don't know how calculate frequency and duty cycle in the circuit. ...
0
votes
3answers
1k views

Using a NE555 for 12V boost to 24V to power an amplifier

I'm trying to draw a supply scheme for a class D integrated amplifier. It requires 21V to 24V power supply and about 6/7A of current at 24V. The input is a car battery: 10V to 14.4V. I found this ...
3
votes
2answers
631 views

NE555 above 100kHz frequency problem

At first I searched this problem and could not find anything with this specific. I am using NE555 to generate frequencies. I'm using the calculations of this website. I am using 10nf as it says. My ...
-3
votes
1answer
269 views

Constant power supply with countdown timer triggered by a momentary switch

Can I make a 1 or 2 NE555 timer delay switch adjustable module from eBay,or any other simple components ? Momentary switch closes = power ON and start of a countdown timer of 0.3s. Mentary switch ...
0
votes
1answer
60 views

Two Astable NE555 Affects one another

I have two separate breadboards, on each breadboard I placed NE555 and both are configured in astable mode. Breadboard 1 is configured to 200Hz @ 50% duty cycle and Breadboard 2 is configured to 1....
0
votes
1answer
205 views

Photoresistor with NE555

I would like to build a circuit with two blinking LEDs using a NE555 timer and a photoresistor. In the schematic below the blinking frequency becomes higher when more light shines on the photoresistor ...
0
votes
1answer
130 views

NE555P Frequency Drop to 0 after a couple of minutes? [closed]

I'm trying to build a frequency measurement circuit using NE555P and Atmega328P. The circuit is the following : I use this library https://www.pjrc.com/teensy/td_libs_FreqCount.html Always, The ...
2
votes
1answer
694 views

Offline Flyback DC-DC converter using NE555, Works in LTSpice, will it work in a real world application?

I'm currently a novice and am learning EE. I've been experimenting with low voltage DC-DC converters. Now I want to build an offline DC-DC converter that operates directly from AC mains. The ...
-2
votes
3answers
236 views

What would be the lowest cost approach to a low power, up to months-long timer?

I'm looking for a starting point. I wish to make a very small circuit (SMD, something like 2cm x 2cm PCB) low cost (translating to hopefully well < $1 at production). The circuit would provide a ...
3
votes
2answers
787 views

Question about comparator and 555 timer circuit

I'm designing my first circuit for a university project. This circuit will check the voltage of two sensors. If both are over a reference voltage and persist as such for more than one second, a relay ...
-1
votes
1answer
1k views

555 - Adjusting frequency without affecting duty cycle

This seems to be some easy thing someone figured out already, but here I am after an hour of searching - and fearfully asking the question. My aim is to build a relatively simple 555 circuit using as ...
1
vote
3answers
1k views

Slowly ramp up the PWM duty cycle with a 555

I have a PWM signal being generated by a 555 timer and that is fed into a ESC for an electric skateboard. My problem is that the PWM signal duty cycle can go from 5% to 95% in a fraction of a second. ...
3
votes
3answers
1k views

Output frequency unstable in 555 oscillator

I'm trying to make a simple astable NE555. The output frequency increasing alone. For example it start from for example 4.2 kHz and immediately change to 4.3 kHz, 4.6 kHz, 5kHz, then play around 4.5 ...
0
votes
2answers
139 views

Radioshack 555 Timers

So I went to RadioShack recently because they were having a 40-80% off liquidation/closing sale. I picked up quite a few things, and one was a 555 timer for a decent discount from its already low ...
0
votes
2answers
222 views

CD4017 Decade Counter Based LED Flasher Question

I am creating a simple LED Flasher with NE555 and CD4017. I am actually dividing the pulse frequency of NE555 by five. Because I have merged each pair of the output pins to finally get 5 outputs. I ...
0
votes
4answers
310 views

Lighthouse LED simulator [closed]

I want to make an LED flash twice every ten seconds to the following character * On 750ms approx, Off 1s , On 750ms approx, Off 7500ms, Repeat. * I am fully aware how to do this with a ...
0
votes
0answers
930 views

Need Help with PWM Motor Speed Controller Circuit

I am using the following circuit to make my PWM Motor Speed controller. I just replaced the MOSFET IRF510 with IRF540 and LM555 with NE555. I found the schematic on the web. My motor is 12V rated and ...
0
votes
1answer
86 views

5V to the discharge pin, threshold pin and trigger pin

What happens if I give 5V to the discharge pin, threshold pin and trigger pin of 555 without giving power at pin 8 and grounding at pin 1?
1
vote
1answer
81 views

Control an inductive load with VCO

I am trying to tune this circuit, dimensioning the values of resistors Ra,Rb and the capacitor C... The circuit work in this way: a voltage Vin regulates the current flowing in the inductor, via the ...
0
votes
2answers
216 views

What causes inaccurate time in 555?

I would like to use 555 with a relay to make a reliable control circuit. I use 555 as mono-stable and the following equation does not work: t = 1.1*R*C seconds R = 51 K ohm C= 220 uF The ...
0
votes
1answer
89 views

Why I am seeing a spike of 9V on output and capacitor in 555 timer

I would like to have high voltage at output initially for a period of time, then low and high ... . But in the following circuit, I see spikes on output (green) and capacitor (blue) for a short period ...
1
vote
1answer
824 views

Power calculation of circuits

Please read on..... this looks long but is entry level and easy I have done many simple projects based on microcontrollers but have not considered power and required current(for circuit to work) ...
2
votes
1answer
166 views

Circuit for auto repeat switch off/on USB Data-

I recently aquired an APC UPS and connected it to my (Mac) server through USB. However, the load percentage is only updated (via pmset -g ps) when unplugging/plugging the USB cable. I found out it's ...
0
votes
2answers
297 views

I need some help calculating values for a variable 555 oscillator circuit

For the past few hours i have been strugling with a 555 timer. What i am trying to do is generate a square wave of variable frequency controlled by a potentiometer. At the time i have a 200KΩ ...
0
votes
1answer
1k views

60hz Astable 555 timer circuit not oscillating

Yet another electronics newbie here :) I have tried to construct a simple 60Hz oscillator using a NE555 timer in astable mode, yet it does not seem to be oscillating. To test it, it has been connected ...
0
votes
1answer
1k views

Metal detector working explanation

Please explain to me the working of this metal detector circuit. Also,I have constructed this circuit but the problem is that I am getting the output(speaker) even when coil is disconnected from the ...
2
votes
1answer
284 views

NE555 speaker voltage spikes

I made a NE555 circuit with speaker. It works fine, but when I connect its output to the oscilloscope, I get this view: How could I reduce these voltage spikes? How can I get nice square waves? Or ...