High-frequency flip=flop with ring of transistors - has base coupled to collector via separate resistor

摘要

The h.f. flip flop has a chain of transistors with the base of one coupled via a resistor to the collector of the next to form a closed ring. The emitters of the transistors are coupled to a first shared supply rail and their collectors are connected via separate collector resistors to a second shared supply rail. The output is taken from the collector of one of the transistors. During operation, T1 is conducting and its collector is at level 0 so that T3 draws no current since its collector is at level 1, which means that T1 turns off. To can now turn on and its collector goes to 0 and T2 switches off.