The figure shows how to drive a load up to 300 mA with an LM3900. The transistor can be a BD136. We found this setting in the 1994 National Semiconductor Linear Applications Handbook.
We found this frequency meter circuit in a 1974 documentation. The circuit is powered by 12 V and...
This high gain small signal amplifier circuit was found in an old publication on transistors....
This circuit can be used with input voltages up to 750 V, regulating the current between 200 uA...