555 timer tone generator ???

T

Jan 1, 1970
0
Use a PIC, of course.

555 timers have been utterly and totally useless for two decades now.

Just like most of the rest of us. :-D

D

Don Lancaster

Jan 1, 1970
0
Anthony said:
Don Lancaster wrote:

And there you have it everyone. You should revamp/amend your awesome book
line-up with a complete set of PIC cookbooks. I would really enjoy a "PIC
Active Filter Cookbook". ;-)

Books do not sell worth shit these days.

Real world author return is an order of mangitude or more less than before.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552

Please visit my GURU's LAIR web site at http://www.tinaja.com

J

jasen

Jan 1, 1970
0
Hello,

My name is Tom and I am new to this group. Please forgive my
newbieness. I am an Industrial controls tech with limited electronics
knowledge.

I was hoping I could get some help designing a simple tone generator
for a unique application. I have so far built a simple tone generator
using a 555 timer chip and some resistors and caps with a circuit I
found online. I am using pin 5 to control it as a VCO astable.
Everything works great, the input dc voltage is varying the tone, but
I want the frequency to go up with voltage. Kind of like an audio
voltage monitor. This input voltage is about 0-14 volts. The problem
is that the frequency goes down when the voltage goes up. Just the
opposite of what I need.
try this:

+5v
|
.-[47K]-+----------+
| | . . . .|. . . .
| | . VCC(8) .
| | . .
| ----RES(4) OUT(3)--------- out
| . 555 .
in -[100K]-+-------+----TH(6) DIS(7)----.
| . . |
+----TR(2) CV(5)--+ |
| . . | |
| . GND(1) . | |
| . . . .|. . . . | |
| | | |
| 100n +--||----' |
+---||-----+ 10n |
| | |
--[10K]---)----------'
|
---+-- gnd 0v
//////

Increase the 47K to 51K to make it silent with Ov input,

Bye.
Jasen

J

John Popelish

Jan 1, 1970
0
jasen said:
try this:

+5v
|
.-[47K]-+----------+
| | . . . .|. . . .
| | . VCC(8) .
| | . .
| ----RES(4) OUT(3)--------- out
| . 555 .
in -[100K]-+-------+----TH(6) DIS(7)----.
| . . |
+----TR(2) CV(5)--+ |
| . . | |
| . GND(1) . | |
| . . . .|. . . . | |
| | | |
| 100n +--||----' |
+---||-----+ 10n |
| | |
--[10K]---)----------'
|
---+-- gnd 0v
//////

Increase the 47K to 51K to make it silent with Ov input,

Bye.
Jasen

I see how the timing cap charges positive, but how does it
discharge?

M

MooseFET

Jan 1, 1970
0
I'm going to suggest a slight modification.
Modified quoted text:
try this:

+5v
|
.-[47K]---+----------+
| | . . . .|. . . .
| | . VCC(8) .
| | . .
| ----RES(4) OUT(3)--------- out
| . 555 .
in -[100K]-+-+-[10K]-+----TH(6) DIS(7)----.
! | . . |
! +----TR(2) CV(5)--+ |
! | . . | |
! | . GND(1) . | |
! | . . . .|. . . . | |
! | | | |
! | 100n +--||----' |
! ---||-----+ 10n |
! | |
------------------)----------'
|
---+-- gnd 0v
//////

Increase the 47K to 51K to make it silent with Ov input,

The "Out" signal will be a string of pulses. If you wire things up
this way, the time the pulse is low for will be constant with respect
to the input.

In the previous version, the pulse on the Out will get wider as the
voltage increases.

In the modified version, the voltage vs frequency curve have a slope
that gradually decreases when you get near the upper limit. In the
unmodified version, the slope would decrease more rapidly and the
frequency would eventually start to decrease.

T

twilightzonepinball

Jan 1, 1970
0
On 2007-04-02,twilightzonepinball<[email protected]> wrote:

I'm going to suggest a slight modification.
Modified quoted text:

try this:
+5v
|
.-[47K]---+----------+
| | . . . .|. . . .
| | . VCC(8) .
| | . .
| ----RES(4) OUT(3)--------- out
| . 555 .
in -[100K]-+-+-[10K]-+----TH(6) DIS(7)----.
! | . . |
! +----TR(2) CV(5)--+ |
! | . . | |
! | . GND(1) . | |
! | . . . .|. . . . | |
! | | | |
! | 100n +--||----' |
! ---||-----+ 10n |
! | |
------------------)----------'
|
---+-- gnd 0v
//////
Increase the 47K to 51K to make it silent with Ov input,

The "Out" signal will be a string of pulses. If you wire things up
this way, the time the pulse is low for will be constant with respect
to the input.

In the previous version, the pulse on the Out will get wider as the
voltage increases.

In the modified version, the voltage vs frequency curve have a slope
that gradually decreases when you get near the upper limit. In the
unmodified version, the slope would decrease more rapidly and the
frequency would eventually start to decrease.

Does this set up work on 14VDC Vcc?

M

MooseFET

Jan 1, 1970
0
I'm going to suggest a slight modification.
Modified quoted text:
try this:
+5v
|
.-[47K]---+----------+
| | . . . .|. . . .
| | . VCC(8) .
| | . .
| ----RES(4) OUT(3)--------- out
| . 555 .
in -[100K]-+-+-[10K]-+----TH(6) DIS(7)----.
! | . . |
! +----TR(2) CV(5)--+ |
! | . . | |
! | . GND(1) . | |
! | . . . .|. . . . | |
! | | | |
! | 100n +--||----' |
! ---||-----+ 10n |
! | |
------------------)----------'
|
---+-- gnd 0v
//////
Increase the 47K to 51K to make it silent with Ov input,
The "Out" signal will be a string of pulses. If you wire things up
this way, the time the pulse is low for will be constant with respect
to the input.
In the previous version, the pulse on the Out will get wider as the
voltage increases.
In the modified version, the voltage vs frequency curve have a slope
that gradually decreases when you get near the upper limit. In the
unmodified version, the slope would decrease more rapidly and the
frequency would eventually start to decrease.

Does this set up work on 14VDC Vcc?

Yes, the whole circuit scales up and down. If it makes "Y" Hz when the
input is 5V and Vcc is 5V, it will now make "Y" Hz when the input is
14VDC.

The LM555 is rated at IIRC 18V. Check the data sheet of the actual
model you are using. Look for the Absolute Maximum voltage and stay
well below that.

M

MooseFET

Jan 1, 1970
0
jasen said:
try this:
+5v
|
.-[47K]-+----------+
| | . . . .|. . . .
| | . VCC(8) .
| | . .
| ----RES(4) OUT(3)--------- out
| . 555 .
in -[100K]-+-------+----TH(6) DIS(7)----.
| . . |
+----TR(2) CV(5)--+ |
| . . | |
| . GND(1) . | |
| . . . .|. . . . | |
| | | |
| 100n +--||----' |
+---||-----+ 10n |
| | |
`--[10K]---)----------'
^^^^
This guy ------------------
I see how the timing cap charges positive, but how does it
discharge?
Through the 10K I marked.'

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