Just for the hell of it, I wondered if it was possible to substitute the 555 timers in an Atari Punk Console (APC) with some other component, or components.
After seeing some Schmitt-trigger inverters (CD40106) used in oscillator circuits, see Swingers, I thought that I would come up with an alternative design.
An APC consists, basically, of two multivibrators, an astable and a monostable.
Having seen an astable schematic based around a Schmitt-trigger inverter,
From BASIC ELECTRONICS COURSE – THE SCHMITT TRIGGER (Page 49), the frequency of the oscillation is given by 1.2/(RTCT), this is actually incorrect. See also Electronics Tutorials – Waveform Generators, which states that the frequency is given, approximately, by 1/1.2RTCT.
Note that RT would be replaced with a potentiometer, thus allowing the frequency to be changed.
I then only needed to find a monostable based around the same device.
A simple google came up with this schematic, from 40106 Monostable:
40106 MonostableWhen the button is pressed it discharges C1. This brings the input of IC1a to 0Vmaking the output high. When the button is released, C1 begins to charge throughVR1. As C1 charges, the potential at the input of IC1a rises exponentially up to thesupply voltage. When it passes the upper trip point it is interpreted by IC1a as a logic 1 and the output switches to logic 0 where it remains until the push button is pressed again.The time duration of the output pulse is of the order VR1 x C1.Note: Pulse timing begins after the push button is released. This might be undesirable in some situations.
Also, worth a note is problems with a 40106 monostable