The circuit shown consists of a power stage for relay excitation. 2N3053 can be a BD135 and 2N406 can be replaced with a BD136. R3 depends on the trigger voltage.
This circuit consists of a monostable multivibrator using the LM3900 transconductance operational...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...