This circuit was found in a 1970's Radio Electronics. The pulse transformer has a 1: 1 turn ratio. The triac must be in accordance with the controlled load.
We found this circuit in an 80's Radio Electronics. It can still be easily assembled as the used...
This preamplifier for the phonographic capsule was obtained in an Argentine publication from 1973....
The circuit shown in the figure below is suggested by ON Semiconductor (www.onsemi.com), based on...