Many integrated circuits have undocumented features or abilities. This is one of them. The TLC555 output (pin 3) can sink a 100mA load to 1.28V. The open drain transistor reset (pin 7) can sink 100mA ...
Automotive electronic control applications require robust input power conditioning. The circuitry must absorb 100-V transients on one hand, while providing a stable dc bus for a few hundred ...
The relay's primary appeal is its ability to do a lesser-switch's bidding but it's capable of so much more. Relays can be wired together to create very useful, simple, and utterly reliable networks.