How does the Canonet GIII electronically control its mechanical parts?

In A mode, the Canonet GIII prevents the shutter from being released unless the metering is within a certain range (i.e. the available range of apertures it can set).

How does it do that? And how does it set – as in, physically control – the movement of the iris blades?

There has to be some sort of transducer in each case that transforms an electronic condition into a physical one. I think it must be a lever coupled to the movement of the light meter needle, but I can’t remember and I’d have to take one apart to verify this; perhaps someone else can confirm.