This integrating circuit multiplies the time that can be obtained with a 555 timer. We find it in an Electronic Design from the 90s. The circuit uses components that are still common today.
This circuit, suggested by Siemens, allows the activation of 24 V solenoids from TTL LSL signals,...
In the figure we have the way to linearize the response of a TTL port with the use of a feedback...
In the figure we have the original version of an amplifier with high input impedance, 1.2 M ohms....