This crystal configuration can be made with triggers of any logic. The frequency is given by the formula next to the diagram. This setting is specifically for TTL.
The circuit shown uses the 741 operational amplifier, but lower noise and higher gain equivalents...
The circuit shown in the figure modulates a low power infrared LED with TTL signals. The circuit can...
Found in an old American publication, this article is suitable for incandescent lamps. SCRs can be of...