# Simple 555 LED Circuit Help

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#### NGBEnt

##### New Member
Hey guys,

I am fairly experienced with electronics and out-of-PCB circuitry, but when it comes to schematics and creating the circuit; I am lost.

I am trying to make a simple 555 timer circuit powered by a 9V battery. I am looking to create an astable circuit, and I have a schematic. It is attached. I am unsure if this is one I want, and I am also unsure of the parts I need.

I know I need a few resistors, a capacitor or two, and possible other components. This is where I am lost. I am not sure about the level of resistance and capacitance for my resistors and capacitors, respectively, and I am quite clueless as to where to place everything. I am hoping to try and use a PCB, and I have an unprinted one from my supplies.

Also, do companies make custom PCB's for simple circuits like this for a small price, or do I have to order in bulk?

Last edited:

#### crutschow

##### Well-Known Member
There's no attached schematic.

#### NGBEnt

##### New Member
Oops, sorry. I attached it now.

##### Banned
There are many websites that sell basic kits. Do a google search for 555 frequency generator kit.

#### MrDEB

##### Well-Known Member
change componet values

C1 should be an electrolitic capacitor so a componet change is required (electrolytic isn't available)
suggested values for a 1khz output=
R1 = 10K
R2= 715K
C1 = 1uf
total equals a 1khz square wave with 50% duty cycle

#### vortex2009

##### New Member
LED Flasher

Hi There,
I've done a Led Flasher thing, here goes
not that the Previous threads were not right.. here's my bit

Make R1 4k7
R2 10k
C1 in pins one+two a 100uf electrolitic cap
on the out put put a 4.7uf electrolitc cap, and on the end of that capacitor I use a 100ohm resisitor..
with the above equation the Led should Flash 1hz exactly.
HTH
vortex.2009

#### Hero999

##### Banned
suggested values for a 1khz output=
R1 = 10K
R2= 715K
C1 = 1uf
715k is a precision resistor value (<1%), what's the point when the capacitor will have a tolerance of 10% or greater?

#### confounded

##### New Member
total equals a 1khz square wave with 50% duty cycle
It charges C1 through R1 and R2 but discharges through R2, the duty cycle may be close to 50% as R1 is small compared to R2 but it isnt 50%.
You could make both resistors the same value and put a didode across R2 to get closer to 50% if you wanted.

#### Geno

##### New Member
One additional suggestion, take pin 3 of the 555 to the clock input of a J/K flip flop. The output of the flip flop will be a clean square wave and not a saw tooth.

Just my 2-cents worth...

Good luck.
Geno

#### vortex2009

##### New Member
saw tooth

Hi there,

Yes quite right on the sawtooth, bit.. I made a weird sound generator using the Timer chip, and first I done a astable osc) the frequency was about 6khz, and I put a Pot control into a unsual configuration.. and it sweeps the sound up.. BUT the first project^^^ with this device above, I hooked up a second timer in monostable mode.. fed the signal from the monostable from pin two.. to out out of the first astable & from pin 3 on the mono, pin 2 I put on the other part of the out put.. which gave a rising buzzzing..

And do you know I actualy dont know how the mono part works!!! at all but I got the desired sound effect.. YEs its a complex circuit.. but came to light by trial & error... is that cool??

#### vortex2009

##### New Member
error

Hi there,
I apologise, the previous post.. was not related to the chap who wanted a Led Flasher soz about this

regards
vortex2009

#### wombweller

##### Member
Hey guys,

I am fairly experienced with electronics and out-of-PCB circuitry, but when it comes to schematics and creating the circuit; I am lost.

I am trying to make a simple 555 timer circuit powered by a 9V battery. I am looking to create an astable circuit, and I have a schematic. It is attached. I am unsure if this is one I want, and I am also unsure of the parts I need.

I know I need a few resistors, a capacitor or two, and possible other components. This is where I am lost. I am not sure about the level of resistance and capacitance for my resistors and capacitors, respectively, and I am quite clueless as to where to place everything. I am hoping to try and use a PCB, and I have an unprinted one from my supplies.

Also, do companies make custom PCB's for simple circuits like this for a small price, or do I have to order in bulk?

Hi
Schematica Software 555 timer and active filter circuit design and simulation
Mark

#### Virus

##### New Member
LM555 Timer Circuits

This link has excellent tips, theory and diagrams on 555 with calculators etc.

Virus

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