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513 Threads found on edaboard.com: Timer 555
First of all, hi everyone! I'm new in this community and this is going to be my first design as an Electrical Engineer. I'm getting perfect 12VAC signal with 1khz from this circuit. But when I try regulating this 12VAC to 6VDC 1Amps, I'm having huge voltage drops and regulator doesnt work. I think transistors current limits are not enough. Would
Huh? A 555 is a timer, an LM358 is an opamp. Just use a 0.1uF or 0.01uF. It will be fine.
Hi, At first sight according to a datasheet the second schematic design is also correct, but it looks on closer inspection like you need to choose between one load or another - if you think about what'll happen there a little bit. You can use the discharge pin for a second LED, if you do so with a little care. If your circuit doesn't work as p
I am generating 300us Monostable Pulse through 555 IC with 12V Vcc supply.The frequency is 5Hz. The pulse width is ok but when I see the waveform on the oscilloscope, the pulse shape is not good. The pulse rises to 10V very fast but after that exponentially goes to 11V and while discharging it drops down to 3 V fast but then exponentially discharge
I'm trying my first 555 timer project. I was able to get a single LED to flash, however when I try to setup the two LED to go back and forth, the one "LO" Led always stays dimly lit. The instructions say this means the timer chip is bad, however I've tried about 10 different chips and they all do the same thing. Another issue I noted is (...)
I have two PWM sources to control mosfet gate driver. the first source is MCU which isn't connected all the time (when needed)(it is not on the pcb), the second is timer 555 which is connected just when i push the buttons (right or left)(manual control and it is on the pcb). I isolated the two sources with pnp transistors to connect the (...)
Hi, So I am trying to build this circuit and i basically have unlimited resources. I am running into a lot of problems with this however. It seems like every time I take a step in the right direction I take two steps back. I have a working transformer a four stage multiplier and a 555 timer. this circuit is exactly like the one presented in the fir
you can make simple delayed timer by using CD4538 or 555 timer I.C, simple google it and you will find your require circuit Fragrance
It sounds as though you want multi-stage timing cycles. Here is a vast collection of circuits for 555 timer IC:
Could you be more specific? Do you want a digital circuit? An analog circuit? Any constraints? Frequency? A simple 555 timer would do this. So could an FPGA.
Hello, I'm pretty new in electronic field, but I have a question. So I have this circuit that should activate two relays, with one clap. I made a circuit build around a 555 timer, in monostable mode, and when I clap in front of the microphone it gives me at the output a signal that have a duration of 6 sec, exactly what I need. With that signal
A single 4017 IC (decade counter) can turn on your heaters, one at a time, in sequence. The IC has ten output pins, although you would only need 6 pins, each controlling a relay. Apply a pulse to the input pin every 2 hours. Each relay will turn on for 2 hours, then turn off as the next one turns
A laser emits light, so it cannot alarm (think of a torch). The reflected light from a laser can be detected and the breaking or reduction of the received signal can be used to fire up an alarm. The main problem is at the receiving end. The photo detection device will always saturate, which means that if the suns rays get into it, it will always
You could use a 555 timer in conjunction with a CD4017 Johnson counter to sequentially change the voltage on the fan. You would need to experimentally determine the voltage needed to give the desired change in speed since the change in speed is generally quite non-linear with respect to voltage. What is the fan current? Do you want the speed to s
You need to add a comparator IC that has a high input impedance to sense the capacitor voltage without loading it down. The output of the comparator can have 4mA as base current to turn on the transistor that drives a relay that needs up to 40mA. Or use a 555 timer IC to replace your entire circuit.
Choose a 12V relay that is capable of carrying the contact current, the ammeter should tell you this. You have a 12V battery, you need a 555 timer then the only thing to ascertain is the polarity of the LOP signal, is it +12 for good or 0V? I would think that the timer is for starting, so when the engine is cranked the supply remains for (...)
In the datasheet of 555 timer, the reset pin can take voltage upto 1v(max.) to reset. Then why the reset pin is connected to Vcc(12V) for Astable multivibrator mode????
hi, To keep the cost down I would use a 555 timer as a PWM generator for each chain. For only 20mA per LED chain, from a 24Vdc source, a BJT or a 2N7000 MOSFET would be suitable. The frame frequency of the 555 PWM generator could be selected for each LED colour chain. Lots of simple circuits on the web.
help me with resistor and capacitors value:-x using 555timer circuit please
Decide what exact length of time makes a wide pulse. When a pulse begins, wait for that length of time, to see if a pulse drops back to 0V before the time window closes. If it is still high at the end of that time window, then you do not send a pulse. Otherwise you send a pulse. It may be possible to configure a 555 timer IC to do the job.