This circuit provides a delay for the activation of an alarm, giving the owner time to leave the premises. The circuit is from the 1995 Encyclopedia of Electronic Circuits Volume 5.
T1 and T2 can be BC557 and T3 a TIP32 for lamps up to 3 A. The supply is made by voltage of 12 V...
This fourth-order filter was found in American documentation from the 90s. The circuit applies to...
This resistance meter uses a two-transistor oscillator as basic configuration. The tone produced...