Amateur alarm circuit problem...

[RobH]

I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing

The said circuit produces a siren type sound on a buzzer so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing

As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks

 

[RobH]

On 22/11/2020 13:05, RobH wrote:

I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing


The said circuit produces a siren type sound on a buzzer  so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working  version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing


As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks

If anyone has replied to my post, I\'m not seeing them.

 

[Jasen Betts]

On 2020-11-22, RobH <rob@despammer.com> wrote:

I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing

The said circuit produces a siren type sound on a buzzer so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing

As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks

With the 555 it\'s all about woltages, check that the voltages on the
555 inputs (pins 2,6,4, and 5) are what you expect them to be


--
Jasen.

 

[Charlie+]

On Mon, 23 Nov 2020 20:13:49 +0000, RobH <rob@despammer.com> wrote as
underneath :

On 22/11/2020 13:05, RobH wrote:
I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing


The said circuit produces a siren type sound on a buzzer  so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working  version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing


As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks

If anyone has replied to my post, I\'m not seeing them.

Not surprising - you have not made it easy to see exactly what you have
done with the two circuits exactly as built side by side (not a
breadboard picture). Why should anyone waste their time when you cannot
be bothered yourself.

 

[Helmut Wabnig]

On Sun, 22 Nov 2020 13:05:12 +0000, RobH <rob@despammer.com> wrote:

I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

Maybe you want to draw your circuit into Micro-Cap
http://www.spectrum-soft.com/index.shtm

It\'s easy. The run the simulation.
That\'s how the professionals do it. No soldering anymore.

At least you should draw the circuit as you modified it.
I am not sure to understand your description.
w.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing

The said circuit produces a siren type sound on a buzzer so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing

As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks

 

[RobH]

On 24/11/2020 07:02, Charlie+ wrote:

On Mon, 23 Nov 2020 20:13:49 +0000, RobH <rob@despammer.com> wrote as
underneath :

On 22/11/2020 13:05, RobH wrote:
I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing


The said circuit produces a siren type sound on a buzzer  so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working  version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing


As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks

If anyone has replied to my post, I\'m not seeing them.

Not surprising - you have not made it easy to see exactly what you have
done with the two circuits exactly as built side by side (not a
breadboard picture). Why should anyone waste their time when you cannot
be bothered yourself.

This is why I hate asking questions here. No help, just castigated.

 

[RobH]

On 24/11/2020 07:11, Helmut Wabnig wrote:

On Sun, 22 Nov 2020 13:05:12 +0000, RobH <rob@despammer.com> wrote:

I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.



Maybe you want to draw your circuit into Micro-Cap
http://www.spectrum-soft.com/index.shtm

It\'s easy. The run the simulation.
That\'s how the professionals do it. No soldering anymore.

At least you should draw the circuit as you modified it.
I am not sure to understand your description.
w.

Thanks but there is nothing on that site for linux machines.

 

[Andy Burns]

RobH wrote:

> This is why I hate asking questions here. No help, just castigated.

You\'re asking people to compare a schematic circuit diagram to a
breadboard built circuit, that\'s over the threshold most people are
willing to get into.

Why not provide a similar schematic showing your alterations?

 

[RobH]

On 24/11/2020 08:41, Andy Burns wrote:

RobH wrote:

This is why I hate asking questions here. No help, just castigated.

You\'re asking people to compare a schematic circuit diagram to a
breadboard built circuit, that\'s over the threshold most people are
willing to get into.

Why not provide a similar schematic showing your alterations?


Ok, I take your point.

I have added the 10k pot, led and ldr onto the original schematic.
It\'s the best I can do, I\'m afraid, and hope it\'s clear enough.

https://drive.google.com/file/d/1ObLBgJfce4fMPrvRTk5emIRcJzxhNWOt/view?usp=sharing

 

[RobH]

On 24/11/2020 05:40, Jasen Betts wrote:

On 2020-11-22, RobH <rob@despammer.com> wrote:
I built an alarm circuit from a book I bought called Make Electronics by
Charles Platt.

https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing

The said circuit produces a siren type sound on a buzzer so I added an
led through a resistor, a 10k pot and a LDR. I then connected the centre
pin of the 10k pot to pin 2 on the top IC555 shown on the schematic


Working version of the circuit
https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing

As the said circuit was working as I wanted with the ldr and buzzer, I
built another of the same circuit.

On this 2nd circuit, the led goes off when I adjust the 10k pot, but the
sound does not. It does on the first circuit I built.

Thanks


With the 555 it\'s all about woltages, check that the voltages on the
555 inputs (pins 2,6,4, and 5) are what you expect them to be

I don\'t know what the voltages are supposed to be nor expected them to
be, but here are my findings if they are any use;

Pin 2 No Led nor pot 3v,
with led on and pot connected , it fluctuates between 5v and 6.8v
With the led turned off by the pot, 7v decreasing
With the led on, turned on by the pot, between 5v and 6.8v

Pin 4 No Led nor pot 9v,
with led on and pot connected , 9v
With the led turned off by the pot, 9v
With the led on, turned on by the pot, 9v

Pin 5 No Led nor pot, 5.9v
with led on and pot connected , 5.9v
With the led turned off by the pot, 5.9v
With the led on, turned on by the pot, 5.9v

Pin 6 No Led nor pot, 3v
with led on and pot connected , between 5v and 6v
With the led turned off by the pot, 5.5v
With the led on, turned on by the pot, between 5.2v an 6.5v

 

[Rich]

RobH <rob@despammer.com> wrote:

On 24/11/2020 08:41, Andy Burns wrote:
RobH wrote:

This is why I hate asking questions here. No help, just castigated.

You\'re asking people to compare a schematic circuit diagram to a
breadboard built circuit, that\'s over the threshold most people are
willing to get into.

Why not provide a similar schematic showing your alterations?


Ok, I take your point.

I have added the 10k pot, led and ldr onto the original schematic.
It\'s the best I can do, I\'m afraid, and hope it\'s clear enough.

https://drive.google.com/file/d/1ObLBgJfce4fMPrvRTk5emIRcJzxhNWOt/view?usp=sharing

It is miles better than your textual description in your original post.

Here is what you said initially:

so I added an led through a resistor, a 10k pot and a LDR. I then
connected the centre pin of the 10k pot to pin 2 on the top IC555
shown on the schematic

However, your new schematic above does *not* show the center pin of the
10k pot connected to pin 2 of the top 555. It shows the center pin of
the 10k pot connected to the positive voltage rail, and the positive
voltage rail connected to pin 2 of the 555. Note also that your
annotations are wrong. You have the line to pin 2 annotated as \"to
pin 3\" and the wire to pin 3 annotated as \"to pin 2\".

So, either your textual description is wrong, or your new schematic
drawing additions are wrong. But you can\'t expect anyone here to be of
much help when you provide incorrect information at the outset.

If you\'ve built the circuit like you show in the new schematic, the top
555 will not do anything, because pin 2 is the trigger input, and you
have it shown as strapped to the positive voltage rail. So the upper
555 simply will not oscillate.

Also, your schematic shows no bypass capacitors for the 555\'s. You\'ve
left out another critical bit of information. Are you using bipolar
555\'s or CMOS 555\'s? Because if you are using bipolar 555\'s, you\'ll
very much want to add bypass cap\'s across the 555 power rails.

Also, another tip, when positing schematic pictures here asking for
help, it is best to add numbers to all the components (i.e., R1, R2,
C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
with which to refer to specific items on the schematics.

 

[RobH]

On 24/11/2020 16:43, Rich wrote:

RobH <rob@despammer.com> wrote:
On 24/11/2020 08:41, Andy Burns wrote:
RobH wrote:

This is why I hate asking questions here. No help, just castigated.

You\'re asking people to compare a schematic circuit diagram to a
breadboard built circuit, that\'s over the threshold most people are
willing to get into.

Why not provide a similar schematic showing your alterations?


Ok, I take your point.

I have added the 10k pot, led and ldr onto the original schematic.
It\'s the best I can do, I\'m afraid, and hope it\'s clear enough.

https://drive.google.com/file/d/1ObLBgJfce4fMPrvRTk5emIRcJzxhNWOt/view?usp=sharing

It is miles better than your textual description in your original post.

Here is what you said initially:

so I added an led through a resistor, a 10k pot and a LDR. I then
connected the centre pin of the 10k pot to pin 2 on the top IC555
shown on the schematic

However, your new schematic above does *not* show the center pin of the
10k pot connected to pin 2 of the top 555. It shows the center pin of
the 10k pot connected to the positive voltage rail, and the positive
voltage rail connected to pin 2 of the 555. Note also that your
annotations are wrong. You have the line to pin 2 annotated as \"to
pin 3\" and the wire to pin 3 annotated as \"to pin 2\".

So, either your textual description is wrong, or your new schematic
drawing additions are wrong. But you can\'t expect anyone here to be of
much help when you provide incorrect information at the outset.

Oops, apologies for the error in the previous schematic of added parts.
I have corrected it now:

If you\'ve built the circuit like you show in the new schematic, the top
555 will not do anything, because pin 2 is the trigger input, and you
have it shown as strapped to the positive voltage rail. So the upper
555 simply will not oscillate.

Also, your schematic shows no bypass capacitors for the 555\'s. You\'ve
left out another critical bit of information. Are you using bipolar
555\'s or CMOS 555\'s? Because if you are using bipolar 555\'s, you\'ll
very much want to add bypass cap\'s across the 555 power rails.

As I said in my OP I built the circuit from an article in a book I
bought several months ago, and it doesn\'t say to use CMOS 555\'s or
bipolar 555\'s, but just 555\'s.

https://drive.google.com/file/d/1O4LWsY41SLjjMaRgLAbh7kONCRkAx9LR/view?usp=sharing

Also, another tip, when positing schematic pictures here asking for
help, it is best to add numbers to all the components (i.e., R1, R2,
C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
with which to refer to specific items on the schematics.

I\'ve named the added 320 ohm resistor as R1, and both the led and the
10k pot centre pin is connected to pin 3 on the 555

https://drive.google.com/file/d/1OyIH7dWiGtX08ytolqDMsCqT-tQxg8nz/view?usp=sharing


Thanks

 

[Jeroen Belleman]

On 2020-11-24 21:35, RobH wrote:

On 24/11/2020 16:43, Rich wrote:
RobH <rob@despammer.com> wrote:
On 24/11/2020 08:41, Andy Burns wrote:
RobH wrote:

This is why I hate asking questions here. No help, just castigated.

You\'re asking people to compare a schematic circuit diagram to a
breadboard built circuit, that\'s over the threshold most people are
willing to get into.

Why not provide a similar schematic showing your alterations?


Ok, I take your point.

I have added the 10k pot, led and ldr onto the original schematic.
It\'s the best I can do, I\'m afraid, and hope it\'s clear enough.

https://drive.google.com/file/d/1ObLBgJfce4fMPrvRTk5emIRcJzxhNWOt/view?usp=sharing

It is miles better than your textual description in your original post.

Here is what you said initially:

so I added an led through a resistor, a 10k pot and a LDR. I then
connected the centre pin of the 10k pot to pin 2 on the top IC555
shown on the schematic

However, your new schematic above does *not* show the center pin of the
10k pot connected to pin 2 of the top 555. It shows the center pin of
the 10k pot connected to the positive voltage rail, and the positive
voltage rail connected to pin 2 of the 555. Note also that your
annotations are wrong. You have the line to pin 2 annotated as \"to
pin 3\" and the wire to pin 3 annotated as \"to pin 2\".

So, either your textual description is wrong, or your new schematic
drawing additions are wrong. But you can\'t expect anyone here to be of
much help when you provide incorrect information at the outset.

Oops, apologies for the error in the previous schematic of added parts.
I have corrected it now:

If you\'ve built the circuit like you show in the new schematic, the top
555 will not do anything, because pin 2 is the trigger input, and you
have it shown as strapped to the positive voltage rail. So the upper
555 simply will not oscillate.

Also, your schematic shows no bypass capacitors for the 555\'s. You\'ve
left out another critical bit of information. Are you using bipolar
555\'s or CMOS 555\'s? Because if you are using bipolar 555\'s, you\'ll
very much want to add bypass cap\'s across the 555 power rails.

As I said in my OP I built the circuit from an article in a book I bought several months ago, and it doesn\'t say to use CMOS 555\'s or bipolar 555\'s, but just 555\'s.

https://drive.google.com/file/d/1O4LWsY41SLjjMaRgLAbh7kONCRkAx9LR/view?usp=sharing

Also, another tip, when positing schematic pictures here asking for
help, it is best to add numbers to all the components (i.e., R1, R2,
C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
with which to refer to specific items on the schematics.


I\'ve named the added 320 ohm resistor as R1, and both the led and the 10k pot centre pin is connected to pin 3 on the 555

https://drive.google.com/file/d/1OyIH7dWiGtX08ytolqDMsCqT-tQxg8nz/view?usp=sharing


Thanks

You never actually stated what your modifications are supposed
to accomplish. Doesn\'t Platt explain how the 555 works? Doesn\'t
he explain how IC pins are numbered? Doesn\'t he explain how to
identify the connections on a potentiometer? Doesn\'t he explain
what LEDs are and how to use them? All of those are the things
you got wrong. There are probably more, hard to tell.

For an older electronics professional, it is sometimes good to
be reminded how many errors a beginner can make. I had your
problems fifty years ago. (No, I didn\'t have 555s then.)

Jeroen Belleman

 

[Ralph Mowery]

In article <rpjvf8$1qpc$1@gioia.aioe.org>, jeroen@nospam.please says...

For an older electronics professional, it is sometimes good to
be reminded how many errors a beginner can make. I had your
problems fifty years ago. (No, I didn\'t have 555s then.)

Jeroen Belleman

Being invented in 1971 it is almost 50 years ago.

That is another cockroach that will not die.

 

[Rich]

RobH <rob@despammer.com> wrote:

On 24/11/2020 16:43, Rich wrote:
However, your new schematic above does *not* show the center pin of
the 10k pot connected to pin 2 of the top 555. It shows the center
pin of the 10k pot connected to the positive voltage rail, and the
positive voltage rail connected to pin 2 of the 555. Note also that
your annotations are wrong. You have the line to pin 2 annotated as
\"to pin 3\" and the wire to pin 3 annotated as \"to pin 2\".

So, either your textual description is wrong, or your new schematic
drawing additions are wrong. But you can\'t expect anyone here to be
of much help when you provide incorrect information at the outset.

Oops, apologies for the error in the previous schematic of added parts.
I have corrected it now:

Are you sure you have. Your new schematic photo now shows a dead short
between the positive and negative power rails, and does not show three
pins on the 10k pot (so no center pin connected anywhere.

Also, your schematic shows no bypass capacitors for the 555\'s. You\'ve
left out another critical bit of information. Are you using bipolar
555\'s or CMOS 555\'s? Because if you are using bipolar 555\'s, you\'ll
very much want to add bypass cap\'s across the 555 power rails.

As I said in my OP I built the circuit from an article in a book I
bought several months ago, and it doesn\'t say to use CMOS 555\'s or
bipolar 555\'s, but just 555\'s.

The question was quite clear, but perhaps you missed it, so I\'ll repeat
it below:

Are you using bipolar 555\'s or CMOS 555\'s?

https://drive.google.com/file/d/1O4LWsY41SLjjMaRgLAbh7kONCRkAx9LR/view?usp=sharing

Also, another tip, when positing schematic pictures here asking for
help, it is best to add numbers to all the components (i.e., R1, R2,
C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
with which to refer to specific items on the schematics.


I\'ve named the added 320 ohm resistor as R1, and both the led and the
10k pot centre pin is connected to pin 3 on the 555

https://drive.google.com/file/d/1OyIH7dWiGtX08ytolqDMsCqT-tQxg8nz/view?usp=sharing

This schematic shows only two of three pins of the pot (presumably you
have a three pin pot, as you did begin with \"center pin of pot
connected...\"

But with the dead short in this version across the power rails (if the
schematic matches how you have it wired), all you will achieve from
this version is warming up your power supply (or blowing it up,
depending on whether it tolerates a dead short).

 

[Phil Hobbs]

On 11/24/20 4:54 PM, Jeroen Belleman wrote:

For an older electronics professional, it is sometimes good to
be reminded how many errors a beginner can make. I had your
problems fifty years ago. (No, I didn\'t have 555s then.)

And you had to make protons go round and round in mason jars.

Cheers

Phil Hobbs

\"In my day, we defragged hard disks by editing the inodes by hand. With
magnets\"


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[RobH]

On 25/11/2020 04:42, Rich wrote:

RobH <rob@despammer.com> wrote:
On 24/11/2020 16:43, Rich wrote:
However, your new schematic above does *not* show the center pin of
the 10k pot connected to pin 2 of the top 555. It shows the center
pin of the 10k pot connected to the positive voltage rail, and the
positive voltage rail connected to pin 2 of the 555. Note also that
your annotations are wrong. You have the line to pin 2 annotated as
\"to pin 3\" and the wire to pin 3 annotated as \"to pin 2\".

So, either your textual description is wrong, or your new schematic
drawing additions are wrong. But you can\'t expect anyone here to be
of much help when you provide incorrect information at the outset.

Oops, apologies for the error in the previous schematic of added parts.
I have corrected it now:

Are you sure you have. Your new schematic photo now shows a dead short
between the positive and negative power rails, and does not show three
pins on the 10k pot (so no center pin connected anywhere.

Also, your schematic shows no bypass capacitors for the 555\'s. You\'ve
left out another critical bit of information. Are you using bipolar
555\'s or CMOS 555\'s? Because if you are using bipolar 555\'s, you\'ll
very much want to add bypass cap\'s across the 555 power rails.

As I said in my OP I built the circuit from an article in a book I
bought several months ago, and it doesn\'t say to use CMOS 555\'s or
bipolar 555\'s, but just 555\'s.

The question was quite clear, but perhaps you missed it, so I\'ll repeat
it below:

Are you using bipolar 555\'s or CMOS 555\'s?

https://drive.google.com/file/d/1O4LWsY41SLjjMaRgLAbh7kONCRkAx9LR/view?usp=sharing

Also, another tip, when positing schematic pictures here asking for
help, it is best to add numbers to all the components (i.e., R1, R2,
C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
with which to refer to specific items on the schematics.


I\'ve named the added 320 ohm resistor as R1, and both the led and the
10k pot centre pin is connected to pin 3 on the 555

https://drive.google.com/file/d/1OyIH7dWiGtX08ytolqDMsCqT-tQxg8nz/view?usp=sharing

This schematic shows only two of three pins of the pot (presumably you
have a three pin pot, as you did begin with \"center pin of pot
connected...\"

But with the dead short in this version across the power rails (if the
schematic matches how you have it wired), all you will achieve from
this version is warming up your power supply (or blowing it up,
depending on whether it tolerates a dead short).

Is this any clearer:

https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing

If it\'s not then , I\'ll just forget about it, as it was only something I
wanted to do while in lockdown.

I didn\'t miss your question about the 555\'s as I answered you:

As I said in my OP I built the circuit from an article in a book I
bought several months ago, and it doesn\'t say to use CMOS 555\'s or
bipolar 555\'s, but just 555\'s.

In case you missed my OP, I already built the said circuit previously
and have it working fine.

Thanks anyway

 

[Jeroen Belleman]

On 2020-11-25 09:10, Phil Hobbs wrote:

On 11/24/20 4:54 PM, Jeroen Belleman wrote:


For an older electronics professional, it is sometimes good to
be reminded how many errors a beginner can make. I had your
problems fifty years ago. (No, I didn\'t have 555s then.)

And you had to make protons go round and round in mason jars.

Cheers

Phil Hobbs

\"In my day, we defragged hard disks by editing the inodes by hand. With magnets\"

In those days, I had no idea that one could become a \'physicist\'.
There were no engineers or academics in my environment, or my
choices might have been quite different. I discovered the very
existence of labs dedicated to physics research when I was 19
years old, quite accidentally as a side effect of my negligence
to secure a local position as a technical student. It turned out
to be a lucky strike.

Jeroen Belleman

 

[RobH]

On 25/11/2020 09:40, Jeroen Belleman wrote:

On 2020-11-25 09:10, Phil Hobbs wrote:
On 11/24/20 4:54 PM, Jeroen Belleman wrote:


For an older electronics professional, it is sometimes good to
be reminded how many errors a beginner can make. I had your
problems fifty years ago. (No, I didn\'t have 555s then.)

And you had to make protons go round and round in mason jars.

Cheers

Phil Hobbs

\"In my day, we defragged hard disks by editing the inodes by hand.
With magnets\"



In those days, I had no idea that one could become a \'physicist\'.
There were no engineers or academics in my environment, or my
choices might have been quite different. I discovered the very
existence of labs dedicated to physics research when I was 19
years old, quite accidentally as a side effect of my negligence
to secure a local position as a technical student. It turned out
to be a lucky strike.

Jeroen Belleman

Aah, well I was a mechanical engineer for over 40 years, and I can read
drawings including schematics. I can\'t draw tho\'.

 

[Jeroen Belleman]

On 2020-11-25 10:19, RobH wrote:

On 25/11/2020 04:42, Rich wrote:
[...]

The question was quite clear, but perhaps you missed it, so I\'ll
repeat it below:

Are you using bipolar 555\'s or CMOS 555\'s?
[...]

Is this any clearer:

https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing

If it\'s not then , I\'ll just forget about it, as it was only
something I wanted to do while in lockdown.

I didn\'t miss your question about the 555\'s as I answered you:

As I said in my OP I built the circuit from an article in a book I
bought several months ago, and it doesn\'t say to use CMOS 555\'s or
bipolar 555\'s, but just 555\'s.

In case you missed my OP, I already built the said circuit
previously and have it working fine.

This is becoming a \'dialogue de sourds\'. The question was
\"Are you using bipolar 555\'s or CMOS 555\'s?\". You did *not*
answer that question. Just give us the exact type as read
from the actual DIP you have in there!

You still haven\'t explained what the intended effect of
the added components is. How are we to know what it is
*supposed* to do?

Your picture still leaves much to be desired, hiding several
crucial details. One thing is clear though: The potentiometer
will have little or no effect until it reaches either end.

If the LED lights at all, it will likely be full on or full
off with the potentiometer at either end, and perhaps blink
for intermediate settings. Even so, this abuses the 555, the
potentiometer and the 9V battery. You seem to be trying to
overpower the 555\'s output with the centre tap of the
potentiometer.

Jeroen Belleman