Pulse generator with delay 555 (CB8922E)

We found this circuit in a Hands On Electronics from the 90s. The delay is given by the formulas next to the diagram.

Triangular Oscillator (CB15684E)
The integrated circuit 4136 consists of operational amplifiers of type 741 in the same enclosure and...
100 Hz High Pass Filter (CB14132E)
In the figure we have an active high pass filter of 100 Hz, suggested by National Semiconductor in its 1994...
Zener Coupling (CB4139E)
According to the consulted American publication of the 1980s, a zener diode can be used for DC...