[Eric Wasatonic] had a box of SWB2433 transistors that he had very little information about. In order to discover their properties, he fired up his curve tracer to compare these transistors with more ...

The M-991 is a call progress tone generator integrated circuit for use in telephony systems. The circuit uses low-poser CMOS techniques to generate tones which are digitally controlled and highly ...

[Debraj] needed a simple signal generator for a project he was working on, but didn’t have one handy. He found that the easiest and cheapest way to get clean, reliable signaling was by using something ...

This circuit generates a dual-tone bells ringing similar to most door-bell units. It can be used in many applications other than door-bell. In the Notes below several options will be given in order to ...