3 questions about this LM358 circuit

[RachelAnne289]

I saw an LM358 circuit while browsing the video. Here is a brief copy of the circuit description:

The core of the breathing light circuit is LM358, which includes two independent, high-gain, internal frequency-compensated dual operational amplifiers, which together with the external circuit form a relatively accurate bistable circuit.

​

Here, R3 and R4 constitute the reference divided voltage of the dual operational amplifier 6V, R6 is the operational amplifier feedback resistance, and C1, R5, R6, and R8 determine the frequency of the control breathing lamp. This LM358 circuit is adjusted by potentiometer R8.

After reading this, I get 3 questions:
1. How can I add more LEDs?
2. Can this capacitor be used with a patch?
3. Is the potentiometer R8 package included in the library?

Anyone can help? Thank you in advance.

 

[danadakk]

I saw an LM358 circuit while browsing the video. Here is a brief copy of the circuit description:

The core of the breathing light circuit is LM358, which includes two independent, high-gain, internal frequency-compensated dual operational amplifiers, which together with the external circuit form a relatively accurate bistable circuit.

​

View attachment 168918

Here, R3 and R4 constitute the reference divided voltage of the dual operational amplifier 6V, R6 is the operational amplifier feedback resistance, and C1, R5, R6, and R8 determine the frequency of the control breathing lamp. This LM358 circuit is adjusted by potentiometer R8.
View attachment 168919
After reading this, I get 3 questions:
1. How can I add more LEDs?
2. Can this capacitor be used with a patch?
3. Is the potentiometer R8 package included in the library?

Anyone can help? Thank you in advance.

1) Yes. Circuit though should have D1-D4 all in series, same with D5-D8, to insure ~ equal brightness
in all leds. You would add more in series depending on Vcc value. How many more do you want to
add ? What color are they (their forward voltage varies a lot with color used).

2) What is a patch ?

3) What library ?

4) Is this being used as flashing LEDs ? If so a more accurate solution would be to use a
micro that can control flashing rate closer to a few %. An ATTINY85 or an Arduino Nano
board would handle this quite easily. Code with mBlock this simple -

Interface to UP would look something like (note R1 would be something less depending
on current you want and V1 power) -

5) What current range LEDs do you plan to use ? High power or a few mA type ?

There is a circuit description that says circuit is "relatively accurate". Where timing is
controlled by a off the shelf electrolytic one would not use the word "accurate" to des-
cribe timing based on it.

Regards, Dana.