Questions tagged [555]

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation and oscillator applications. The part is still in widespread use, thanks to its ease of use, low price and good stability. The 556 timer is simply two 555 timers in a single package.

Filter by
Sorted by
Tagged with
0
votes
1answer
1k views

Driving MOSFET with 555 timer [duplicate]

I am building a plasma speaker using a 555 timer to generate the audio tone. I am driving a mosfet with the output of the 555 timer, which in turn powers a flyback transformer to generate a plasma ...
0
votes
1answer
1k views

Simulation error and output voltage drop of DC voltage doubler circuit in Multisim

I have simulated the circuit provided in this link:http://www.circuitdiagram.org/dc-voltage-doubler-multiplier-circuit.html. But, when I simulate the circuit, the output voltage is dropped and I get a ...
0
votes
1answer
113 views

555 timer accident

I accidently applied around 5V to the output pin of the 555 timer.The output is zero when I ground the trigger, and an LED connected between 5V and pin 7 will not respond when 5V is applied to the ...
0
votes
1answer
788 views

Variable Timer Circuit w/ Digital Display for Counting Down

I would like to make a timer. The timer will have a 7 segment digital display and will work with a microcontroller of some sort. I would like to be able to put in a time (e.g. anywhere between 0 - ...
0
votes
1answer
117 views

NE555 Timer Problem

I need help using an NE555 timer to flash an LED. Here is my current set up: All resistors are 220 Ohms and LED is link The capacitor is 10uf and same result happens with 1uf. I am using a 9V battery....
0
votes
1answer
1k views

using one 555 timer to control the pulse of another

tried making something like this Limit Number Of Pulses From 555 Or Similar but it doesn't work. I'm not sure what it needs. I'm trying to make the first timer put out voltage to the second one for ...
0
votes
1answer
604 views

Problem in creating one-shot impulse circuit

I am a student in university and I have a problem to be solved. I have to design a circuit that gives just one pulse (not periodic signal) when the 220V source is active. I will give 220V to the ...
0
votes
1answer
752 views

555 timer multivibrator charge and discharge

With this kind of connection I expect 555 to run as a multivibrator. As far as I understand the discharge of the capacitor should be via R2, while charge of the capacitor via R3 and D1. => discharge ...
0
votes
1answer
423 views

IC 555 timer to provide oscillation for high amp electromagnet

I am using a self-built electromagnet in my project that consumes 9.0 amps at supplied voltage of 12 VDC. I don't mind even if amps goes high. The power supply I am using can provide up to 30 amps. I ...
0
votes
3answers
302 views

555 timer not switching at threshold voltage

This is a 555 timer circuit which is supposed to generate two short pulses, back to back, at a regular frequency. The top 555 is configured as astable to control the frequency. It feeds the first 555 ...
-1
votes
3answers
78 views

555 timer oscillator schematic question

I found this schematic, which in theory alternates the LEDs like in railway crossing lights. First of all I was wondering if it works, and if it does, what frequency does it have, and what would I ...
-1
votes
1answer
135 views

Relay sending too many signals.

I have a 555 timer clk output going to the coil of a relay. 5volts going throw the contact. The 5volts is then going to the clock bit of a CD4026 then to a 7 segment display, Seems the relay is ...
-1
votes
1answer
1k views

Simplest (cheapest) adjustable PWM oscillator? [closed]

I'm trying to make an oscillator where I can adjust the frequency and the duty cycle independently, but I'm not having much luck. What I want is a frequency range from 1Hz to 1MHz; and the ability to ...
-1
votes
3answers
2k views

How to trigger something once a day [duplicate]

What would be the right thing to use if I want the base of a transistor to be high for 12 hours and low for 12 hours? I ask because I would like to make a circuit that regulates temperature in a room....
-1
votes
1answer
405 views

H-Bridge: forward and backward dc motor with ic 555 by esp8266 gpio

Searching on web for make h-bridge to forward and backward dc motor with ic 555 by microcontroller ESP8266 GPIO (PWM), i found some helps and i did this circuit: This circuit always stay with +3.95v (...
-1
votes
1answer
53 views

LED blinking circuit design

I am trying monitor activity on Rx/Tx lines of UART signals with led's. I have more number of channels(20) so i dont have place to use micro controller for this purpose. NE556 timer in monostable ...
-1
votes
1answer
384 views

What is 0.693, and 1.1, and 1.44 in IC 555 Calculations

I tried a lot to figure out but could not find any answer to this question anywhere. For calculating pulse width in a standard IC 555 astable and monostable configurations we use the following ...
-1
votes
2answers
819 views

What is the simplest possible monostable 555 timer circuit?

Say for instance, the goal is to light an incandescent bulb for x amount of seconds (let's say 20). What is the simplest configuration possible? Of course, simple timer circuits aren't rare, and can ...
-1
votes
3answers
118 views

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 ...
-1
votes
3answers
165 views

Is it possible to get complementary clock output from a clock generator such as a 555 timer using simple digital logic?

I'd like to get complementary output from a 555 timer. I've seen previous suggestions of using a D Flip Flop, which is a fine suggestion, however that halves the frequency at the outputs of the flip ...
-1
votes
2answers
155 views

555 delayed after threshold goes above control voltage

I am messing around with some 555s I bought a while back (NE555N from STMicroelectronics) and I'm getting some unexpected behavior. I have a capacitor hooked up to both the trigger and threshold pins ...
-1
votes
1answer
8k views

How to design a binary counter with 4029 binary counter ic

I am trying to build a circuit that counts up to 15 or 1111 in binary using a 4029 ic and 4 LEDs as demonstrated in this video. I have studied the 4029 datasheet, and I still can't figure out how to ...
-1
votes
1answer
67 views

555 timer operating voltage

I am trying to build a bistable multivibrator using NE555 timer. The datasheet says the operating voltage should be in the range 4.5V-17V, but during testing I have observed that my circuit works even ...
-1
votes
1answer
64 views

Help using a 555 timer to increment counter that needs to be pulled low

I need a little help with a project. I'm very new to building circuits. I have this NE555 duty-cycle pulse frequency adjustable square wave generator module, which I have connected to a 12V DC source. ...
-1
votes
1answer
87 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 ...
-1
votes
1answer
1k views

How to get more efficiency out of 555 timer + MOSFET?

I needed to build a delay circuit so I'm following this guide: http://www.learningaboutelectronics.com/Articles/555-timer-delay-before-turn-on-circuit.php Using this circuit, I get a delay of about 5 ...
-1
votes
2answers
64 views

Help with count-down clock [closed]

I am quite new to Electrical Engineering and our teacher wanted us to create a circuit diagram. This circuit diagram is supposed to be a 5 minute count-down timer and it is supposed to count-down from ...
-1
votes
2answers
167 views

555 Astable Timer: Why do these two circuits simulate differently?

I've modeled up the following two circuits in LTSpice: simulate this circuit – Schematic created using CircuitLab and... simulate this circuit (I've left out the other connections for ...
-1
votes
1answer
2k 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
votes
2answers
524 views

Adding a sensor to a traffic light circuit?

I am using the current circuit to time a basic traffic light that changes every twenty seconds: However, I've been trying to figure out a way to add a way to detect a car stopping at the light, so ...
-1
votes
1answer
2k views

Problem in Proteus With 555 monostable trigger

I try to make a MonoStable in proteus. Below is my circuit: But my output pulse width is dependent on the trigger circuit. For example in the above circuit according to the formula $$T=1.1RC$$ I ...
-1
votes
1answer
53 views

555 timer question

R1=500k variable resistance R2= 10k when the timer's operation time is 5sec, R1 86.7k What is the operation time when 4V is applied to 5(red point)? im student, so I would very appreciate it if you ...
-1
votes
2answers
203 views

Pull up resistor for 555 Timer IC

https://makezine.com/projects/laser-tripwire-alarm/ I need help determining the pull up resistor needed for this circuit. It uses a 555 Timer IC. The resistor R1 acts as a pull-up resistor for pin ...
-1
votes
1answer
168 views

Atari Punk Console with 7400 chips?

How would I create a stepped tone generator using 7400 logic? For the first part, it's easy to have same range generator, with an additional transistor. Is there any way to make the same range a ...
-1
votes
1answer
263 views

will this voltage tripler circuit work?

I need power supply for my opamp as i only have 5 volt supply. I need at least 14 volt power supply so that i can power my opamp. I recently got this circuit of voltage tripler using 555 IC. Will it ...
-1
votes
1answer
968 views

Servo control without micro controller

I am trying to create a circuit that will control a servo. I need the servo arm to move from 0 to 90 degrees when the power is turned on, and then from 90 back to 0 degrees when the power is turned ...
-1
votes
1answer
265 views

OptoMOS relay issue

I've got this 555 circuit that triggers a high output state for 3 minutes when pin 4 of U14 is pulled low from an open circuit state. I've had it working in the past with U14 as a typical SSR however ...
-1
votes
2answers
166 views

Generation of Digital modulated waves using 555 [closed]

I am confused why there is ppm and digital modulated wave occur at 555 output, when 5th pin is given a triangular signal, instead of connecting it to 0.01uF capacitor. Please tell me which wave (PPM ...
-1
votes
1answer
144 views

Is this circuit a viable implementation? [duplicate]

Following on from an earlier question where the implementation was flawed, can anyone advise if the below is a viable implementation of a circuit to handle a matrix keypad? The idea is that one ...
-2
votes
1answer
86 views

Discharge of capacitor bellow 0.5V

I have a conundrum that I am trying to solve and am afraid I am stuck. Could anyone share some insight please? My circuit is displayed on image above. 5V (5Vsw) and 3.3V (3V3sw) are used as supply ...
-2
votes
3answers
912 views

Sawtooth generator adjustable from 100MHz-500MHz

I need an easy circuit that will generate sawtooth waves at adjustable 100MHz-500MHz (preferably set by a resistor) from 0V going up to 5V. The waves themselves does not have to be perfectly linear, ...
-2
votes
2answers
836 views

How to stop a 555 timer [closed]

I have a 555 timer set up so each cycle it will count up a 7 segment display. clock output of 555 goes to a CD4026B clock input , this feeds the 7 seg display. I would like when the 7-segment ...
-2
votes
1answer
552 views

7805 Voltage Regulator powering astable 555 Timer yields LOW voltage as input to timer circuit

Hello stack exchange, So, I have two batteries powering a circuit and I want to only use one. 12.7V comes from a lead acid battery, and the smaller one is a stack of 4xAA that yield around 6.4V. The ~...
-2
votes
2answers
208 views

555 Astable Period Incorrect [closed]

I set up an astable 555 timer with the output connected to an LED. C1 = 1000 uF, 16V. R1 = 68000 Ohm. R2 = 33000 Ohm. Vcc = 6.5V. By my calculations, the total period should be roughly 93 seconds. But,...
-2
votes
2answers
365 views

Toggling on and off 220V power

I have a 9V 555 timer circuit and I want to use it to automatically turn on and off a 220V water pump. What can I use to connect the timer and the pump? Is there like a transformer or something?
-2
votes
1answer
474 views

Speed and direction control of motor by using IR & 555 on Proteus. (Circuit with errors is attached.)

I am trying to control motor direction & speed by using IR and 555 on Proteus. Circuit and errors images are attached. Please help me solving this quagmire.
-2
votes
1answer
359 views

Momentary switch with IR receiver and transmitter [closed]

I want to make a momentary switch with help of IR receiver and transmitter. I need only a pulse near about 2 seconds and I chose this circuit http://www.meedtech.com/touch-free-timer-switch-circuit/ ...
-2
votes
1answer
215 views

What is the diode for in the astable IC 555

I am trying to get my head into electronics, so my teacher challenged me to find out what this diode does. I have done a ton of experiments and i just cant put my finger on it... Everything from ...
-2
votes
1answer
1k views

Slayer Exciter Circuit [duplicate]

R1 = 2Ω R2 >= 22kΩ D2 = 1N4148, or 1N400x (x is a number) U1 = MIC4452 (MIC4452YN is the through-hole version) Q1 = 2SK2542 So basically I want to run the circuit from a NE555 timer because I don't ...
-2
votes
2answers
164 views

Simple 555 on/off oscillator [closed]

I have heard many people talking about how useful and simple the 555 timer chip is, yet I still cannot find a simple, easy method of creating a circuit that oscillates on and off every hour or so ...