Circulator

The circuit

Circulators are passive non-reciprocal transfer elements. The clockwise connections have low insertion losses while the counter-clockwise connections are isolated. They are used in very high frequency applications where the wavelength approaches the spacing of components. The standing waves then have to be eliminated by separating emerging waves from reflections. Occasionally, circulators are used in telegraphy where a bidirectional transmission path has to be established with a twin wire cable. Transmitter and receiver then have to be isolated from each other by a circulator.

The input file

circulator

.control
tran 0.01ms 2ms
plot v(1)+1 v(2) 200*v(3)-1 xlabel t[s] ylabel 'voltage[V]' title 'TRAN analysis'
.endc

v1 1 0 dc 0 sin 0 1 1kHz

r1 9 4 1k
r2 9 1 1k
r3 4 5 1k
r4 5 6 1k
r5 5 2 1k
r6 6 7 1k
r7 7 8 1k
r8 7 3 1k
r9 8 9 1k
r10 1 0 1.01k
r11 0 2 1.01k
r12 0 3 1.01k

e1 5 0 1 4 1meg
e2 7 0 2 6 1meg
e3 9 0 3 8 1meg

.end

The results