Intercom (CB21660E)

This good gain circuit was found in a Popular Electronics from April 1967. The transistors are germanium of the time.

150 mA LDO Texas Instruments TPS780 (CB15586E)
The Texas Instruments TPS80 LDO (Low Dropout) series (www.ti.com) can provide output voltages from...
Variable Power Supply with Digital Voltmeter (CB17637E)
We do not need to stress the importance of power supplies in the project development laboratory or on the...
Logic Level Indicator (CB1300E)
This circuit, found in documentation from the 1990s, uses a common 7-segment LED display. The...