The 9V supply would work for the LM358 part but the maximum output from it will be close to 5V only. This results in a maximum output 0f 6.2V from the LM317 module (2.2V is the minimum output voltage) ...

Part, too, is digital. So we were discussing a seemingly simple question: How do we best generate a bipolar power source for the op amps on a badge? Like all design requests, this one is unreasonable.

but — for most op amps — you can’t quite get down to the supply rail. If your power options are a positive voltage and ground, you can’t get down to zero without a special kind of op amp ...

A Zen paradox arose: if the addition of a capacitor between ground and the LM317 ADJ pin reduces the power supply-induced ripple current ... Table 1 Desired and simulated DC currents for the circuit.