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.

Acid Rain Monitor (CB25037E)
Written in an article in Radio Electronics magazine in April 1987, this circuit triggers an alarm...
IR Remote Control Receiver (CB25785E)
This is the receiver circuit for the previous transmitter. The circuit has a programming key to...
Temperature Sensor TMP390 (CB20399E)
This is an example of a temperature sensor shield using the Texas Instruments TMP390 obtained from...