We found this circuit in the Texas Instruments optoelectronics manual. Field effect transistors can be BF245 and bipolar BC548. The sensor is a photodiode in the photo-generator mode.
Using two common operationals, such as 741, this circuit serves as a medium control in an...
The crystal in this circuit can have frequencies from 100kHz to 8MHz. Capacitor C2 adjusts the...
This circuit is from a magazine 73 for radio amateurs of the 90s. The circuit generates the high...