My understanding is that in an implosion-type bomb, the core of fissile material was surrounded by separate explosive charges that all needed to be detonated within a microsecond of each other.
Since electrical signals travel at roughly half of light speed, timing the explosion should be trivial. There wouldn’t be anything near a microsecond delay due to the length of wires going from one side of the bomb to another.
So generate the “time to explode” signal anywhere on the bomb, let the wires carry it to each detonator, and enjoy the show!
There obviously must be more too it, since that technology is one of the key components of building a working nuclear bomb, but I don’t know what’s missing.
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> Since electrical signals travel at roughly half of light speed,
And the speed of light is roughly one foot per nanosecond. If it matters, put the same length wire to each detonator.
The real trick is getting the explosion front to converge on the center of the bomb. They did that with wedges of two explosives, with different speeds. So the front takes the same time to get to the inside of the explosives, whether it goes straight in from a detonator or goes the longer distance to points between detonators.
So there were two aspects that proved very tricky. One was generating the simultaneous high-voltage electrical signal that would go down 32 separate pathways within a ten-millionth of a second time interval. To do this they invented what is now called the triggered spark gap switch, and was then called a [low impedance switch](https://patents.google.com/patent/US3956658A/).
The other problem was translating that electrical signal into an explosive detonation. Traditionally this was done with something like primacord, which was basically gunpowder in a cord form. But this was too slow and too unreliable when it came to simultaneous detonation. So they developed the [exploding bridge-wire detonator](https://patents.google.com/patent/US3040660A) which would convert the electrical signal directly into a small explosion with very high simultaneity and reliability. So this setup was highly unusual from an ordnance standpoint — having it be essentially all electrical until the very end of the chain — but as you note, it makes a lot of sense once you’ve decided you need simultaneity and speed.
Lastly, the reliability on all of the above had to be extremely high — one failure and the bomb is a fizzle. So they had to do a lot of quality engineering and experimentation to make it so their confidence that everything would work as expected was much more likely than you’d get in other forms of electronics or ordnance.
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