I have two 555s in astable mode producing two audio tones that are sent to a speaker. The idea is to mix the tones. The power source is a single 9V battery. The problem is that the two 555s interfere with each other.
I added some decoupling capacitors across the VCC and GND pins of each 555 but it looks like I will need 1000uf to separate their signals perfectly. Small capacitors in parallel seem to have no effect.
- Is 1000uf excessive? It feels excessive.
- Are there any other common methods for decoupling?
- Could I avoid the problem entirely if I used an LM358 op amp as an oscillator instead?
EDIT: More information
I have not tried the CMOS 555s but that is probably the easiest solution.
I am using a summing amplifier (op amp) which sums the signals but does not stop the 555s from interfering with each other.