555 PROBLEM

J

Junkmail789

Guest
I got my 555 timer circuit working it's .3 sec per cycle. Problem is I'm
driving a relay that is 5 volts and the timer barely even lights a test LED
I hook up to it. Do I need to run a separate power line besides the output
of the timer to a relay?

I'll do some more research today but if anyone has a place to start it would
be appreciated.
 
I got my 555 timer circuit working it's .3 sec per cycle. Problem is I'm
driving a relay that is 5 volts and the timer barely even lights a test LED
I hook up to it. Do I need to run a separate power line besides the output
of the timer to a relay?

I'll do some more research today but if anyone has a place to start it would
be appreciated.
Click to expand...
This should do the trick. You need protection from the inductive kick of the
relay, and the 555 drive current may not be enough to drive the relay. If your
relay coil is less than 100 ohms, you might want to do something else. The two
resistors coming from pin 3 of the 555 could be 1K to 2.2K.

View in fixed font (M$ Notepad)

VCC VCC VCC VCC
+ + + +
| | | |
.-. 8| 4| |
| | .---o---o----. o------.
| | | | | |
'-' | | | |
| | | - |
| 7 | | ^ |
o----o | | _|_
| | | | RY1|_/_|-
.-. | |3 | |
| | | 555 o----. o------'
| | 6 | | | |
'-'.--o | | |
| | | | .-. |
| | | | | | |
o-o--o | | | '---o
| 2 | | '-' |
| | | | |/
--- | | o-----o Q1
--- | | | |>
| '---o--------' .-. |
| 1| 5| | | |
| | --- | | ===
| | --- '-' GND
| | | |
| | | |
| | | |
=== === === ===
GND GND GND GND



created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Good luck.
Chris
 
You could always use a transistor on the output of the timer to drive the
relay.
Brian

"CFoley1064" <cfoley1064@aol.com> wrote in message
news:20031221104437.04365.00001315@mb-m29.aol.com...
I got my 555 timer circuit working it's .3 sec per cycle. Problem is I'm
driving a relay that is 5 volts and the timer barely even lights a test
LED
I hook up to it. Do I need to run a separate power line besides the
output
of the timer to a relay?

I'll do some more research today but if anyone has a place to start it
would
be appreciated.

This should do the trick. You need protection from the inductive kick of
the
relay, and the 555 drive current may not be enough to drive the relay. If
your
relay coil is less than 100 ohms, you might want to do something else.
The two
resistors coming from pin 3 of the 555 could be 1K to 2.2K.

View in fixed font (M$ Notepad)

VCC VCC VCC VCC
+ + + +
| | | |
.-. 8| 4| |
| | .---o---o----. o------.
| | | | | |
'-' | | | |
| | | - |
| 7 | | ^ |
o----o | | _|_
| | | | RY1|_/_|-
.-. | |3 | |
| | | 555 o----. o------'
| | 6 | | | |
'-'.--o | | |
| | | | .-. |
| | | | | | |
o-o--o | | | '---o
| 2 | | '-' |
| | | | |/
--- | | o-----o Q1
--- | | | |
| '---o--------' .-. |
| 1| 5| | | |
| | --- | | ===
| | --- '-' GND
| | | |
| | | |
| | | |
=== === === ===
GND GND GND GND



created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Good luck.
Chris
Click to expand...
 
How can I see your schematic drawing properly?
Brian

"CFoley1064" <cfoley1064@aol.com> wrote in message
news:20031221104437.04365.00001315@mb-m29.aol.com...
I got my 555 timer circuit working it's .3 sec per cycle. Problem is I'm
driving a relay that is 5 volts and the timer barely even lights a test
LED
I hook up to it. Do I need to run a separate power line besides the
output
of the timer to a relay?

I'll do some more research today but if anyone has a place to start it
would
be appreciated.

This should do the trick. You need protection from the inductive kick of
the
relay, and the 555 drive current may not be enough to drive the relay. If
your
relay coil is less than 100 ohms, you might want to do something else.
The two
resistors coming from pin 3 of the 555 could be 1K to 2.2K.

View in fixed font (M$ Notepad)

VCC VCC VCC VCC
+ + + +
| | | |
.-. 8| 4| |
| | .---o---o----. o------.
| | | | | |
'-' | | | |
| | | - |
| 7 | | ^ |
o----o | | _|_
| | | | RY1|_/_|-
.-. | |3 | |
| | | 555 o----. o------'
| | 6 | | | |
'-'.--o | | |
| | | | .-. |
| | | | | | |
o-o--o | | | '---o
| 2 | | '-' |
| | | | |/
--- | | o-----o Q1
--- | | | |
| '---o--------' .-. |
| 1| 5| | | |
| | --- | | ===
| | --- '-' GND
| | | |
| | | |
| | | |
=== === === ===
GND GND GND GND



created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Good luck.
Chris
Click to expand...
 
"Brian Oakley" <brianoakley@ispwest.com> wrote:

How can I see your schematic drawing properly?
Brian
Click to expand...
As Chris said:

View in fixed font (M$ Notepad)
Click to expand...
If not, and you're instead using a *proportional* font, the ASCII
won't line up properly.

And here is a similar schematic in conventional format.
http://www.terrypin.dial.pipex.com/Images/555Astable+Driver.gif

--
Terry Pinnell
Hobbyist, West Sussex, UK
 
Brian Oakley said those words of wisdom from the arcane mages in
sci.electronics.basics:
How can I see your schematic drawing properly?
Brian
Click to expand...
Copy and paste it into Notepad.

--
ChaosŽ - posting from Brazil
wizard_of_yendor.666@hotmail.com
remove the number of the beast - 666
 
If you are using Outlook Express, click View, Text size, Fixed.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
 
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