Understanding the Intel 4004 clock circuit
Noting that the Intel 4004 was normally sold as a chip set called the Intel MCS-4, the standard clock circuit used appears to be this (from this PDF, kindly provided by this vendor of MCS-4 test boards):
Adventures in exploding power supplies
So this went well... The Intel 4004 microprocessor has slightly weird power supply requirements by modern standards. You see, it needs to be supplied with +5V DC, and -10V DC at the same time to work. (It turns out that this is an artifact of the MCS-4 chipset using PMOS technology not the more modern CMOS. Wikipedia has a good description of the constraints of PMOS, but these include the requirement for a number of supply voltages including a relatively negative voltage.) Now, I found this example circuit in someone else's project: Which to me looked quite a lot like these kits from ebay being fed by an AC power supply: So I ordered a kit off ebay, and then ratted around in the garage to find a random AC power supply. Luckily I found one, because they're not super common compared to the DC power supplies I have huge mounds of. Now of course the kit had no assembly instructions apart from the markings on the PCB, which seemed mostly good enough when coupled with some random googling for polarity information. However, I really needed documentation about the input pins. However, that kit appears to be this aliexpress listing, which…