This alarm siren circuit has a latch. We found it in an article in the January 1975 Radio Electronics magazine. Note the power given by Rx and the speaker. It can be increased by changing Q1.
This medium wave commercial receiver from the 1960s was found in a Japanese publication at the...
We found this circuit in a 1967 Electronic Design. The circuit used a MOSFET of the time, which is...
This step of two transistors has a high input impedance due to the use of FET. We can use BF245 for...