now = current_time()
effective_expiry = created_at + ttl_seconds + random_uniform(-jitter_ms, jitter_ms)/1000
if now >= effective_expiry:
    if refresh_policy == "passive" and is_being_accessed():
        refresh_entry()
    else:
        delete_entry()
else:
    return entry

There are several types of TTL models, including:

TTL, or Transistor-Transistor Logic, is a class of digital circuits that are built from bipolar transistors and resistors. They are commonly used in electronic devices for digital logic operations. TTL models are crucial in the design and understanding of digital electronic systems.

TTL models emerged as a significant improvement over earlier logic families like Diode Logic and Resistor-Transistor Logic (RTL). The first TTL family, introduced in the 1960s, offered better performance, higher speed, and lower power consumption. Over the years, TTL has evolved through various series (e.g., 74xx, 74Lxx, 74Hxx) that offer improvements in speed, power consumption, and cost.