Found in old documentation, this circuit is tuned to pass signals below 245 Hz with a level of 0.044 dB above 500 Hz.
This simple injector and signal follower employs a high impedance headset. Transistors can be of...
We found this circuit in a Motorola manual. The circuit employs operationals that are uncommon today...
This circuit is from a manual from the 80's and the operational one used, uncommon nowadays, can...