Several IC circuits from one battery.

Dr. K · Joined: Jan 15, 2020 Posts: 52 Location: wisconsin

I have a working synth module bread boarded up
It's 3 555 square waves, a quad nand, a quad XOR, and a quad op amp. All the function appear to work, but it's super glitchy--I think it's just the rats nest my bread boards turn into.

I want to build a permanent module but had a couple questions about powering them.

I've only been using one fairly large cap between the power and ground busses. On the permanent version, is it good practice to use another cap right near the board?

I also seem to remember using small resistors between the power and each individual circuit. If I remember, it could stop the circuits following each other. (I built a 9v amp years ago, and with a preamp it made a loud TOCK TOCK TOCK sound, but otherwise worked).

An old timer electronics guy I knew in grad school recommended installing a wire, grounded on one end, under the ics to at least partially shield them. I tried tgis with my 4046 vco, and it still was horribly sensitive. Just moving your hands a few inches away would change the pitch.

Ideally I could mount all of them on 1 perfboard.

I've searched for best practices, but am not finding any real hard rules. Ie, don't place components on top of each other...

Grumble · Posted: Tue May 06, 2025 2:50 am Post subject:

Best practice is to connect a capacitor say about 100nF close to the supply pins of each ic and a large one (about 100uF) where the power supply enters the board.
You might want to connect a small filter between the power supply and the supply pins to minimise sugnal feedback.
This filter consists of a small resistor of several ohms, and a capacitor of about 20uF with a 100nF in parallel to this capacitor.