This filter for receiving audio in telegraphy was found in a magazine 73 for radio amateurs, in an edition of the 80s. The circuit is tuned to 700 Hz and has a 200 Hz bandpass.
In the figure we have the way to connect two high power operational amplifiers LM12 to double the...
This circuit uses the Linear Technology LT6505 and was found in a 2005 manual. The circuit is for 24 V...
a This circuit was obtained from a 1978 Practical Wireless. It causes a low-power 1.5V lamp to...