Use a NAND Gate to get a square wave oscillator. Typically, the 4093 is used due to it being a Schmitt Trigger and there being 4 of them in the IC package. The potentiometer allows for user-adjustable frequency control. Lots of uses for this circuit building block.
Use this circuit with your circuits to output a staircase-style CV. The 4516 Binary UP/DOWN Counter is controlled by a two 4093 CMOS NAND Gate oscillators; one controls the clock speed, the other controls the direction of the binary count. A R-2R resistor ladder converts the binary output into a scalable voltage, which is then limited by a potentiometer and buffered for use with synthesizers that can accept a Control Voltage.
The 555 timer can be configured with external components to output a single pulse for a fixed duration. When the switch is toggled to “ON”, the output will go high/1/ON for a brief moment of time, then go back to its stable state. You may find that some switches will need to be debounced, which is a pain in the ass reality of dealing with physical components.
A simple switching circuit that allows you to route a signal to two different paths. LEDs help indicate which signal path is active, although this circuit can also be used without battery/DC Jack power.