We found this circuit in the December 1994 Electronics Now magazine. The worthless components are frequency dependent.
The critical component of this circuit is the transformer. T1 and T2 can be BD135 and T3 / T4 can...
The figure shows how to implement an R-S flip-flop or bistable reset-Set with an LM3900...
This circuit was found in a 1987 documentation but uses components quite common in the current...