Found in Electronic Design, this circuit with the 555 has the extended times by using the transistor in the timing network.
Found in a Maxim documentation from the 1990s, this current-sensing amplifier uses components from the...
We found this circuit in a 1982 documentation. An intercom to be good must be sensitive and have...
This circuit is from a 1980s documentation, but the configuration can be applied to most modern...