This 1970 Electronic Design circuit uses a varactor or varicap. The circuit divides the frequency of a 150 MHz signal by 2. Similar versions appear on this site.
This circuit shows how to use the 4007 MOSFETs in an amplifier stage. We found it in an...
Standardized Software API and Flexible Device Control Methods Allow Customers to Focus on...
This source draws a fixed constant current of 1 mA using a Norton operational amplifier. Other...