Relay computers - telephone type

[Steve Thatcher]

another comment about telephone relays that I played with when I was twelve 
(38 years ago) had a built in speed limitation. You could connect them up 
in a buzzer fashion (power to coil through one of the contact sets) and the 
relay would always make connect to the other pole of the switch and the 
effect was to oscillate at around 10hz or so. You could not make them buzz 
as you can normal relays. This guaranteed make capability was handy in 
creating what I called a holding circuit. You could power the relay on and 
use one contact set to connect power up to make the relay latch.

best regards, Steve Thatcher