This test circuit was found in the PE Hobbyst Handbook in a 1990s edition. The circuit tests the battery under load. The load, as the battery is selected by the switch.
The filter shown in the figure, using only an operational amplifier, is characterized by allowing 1...
Found in a 90s American documentation, this circuit can be used as a shield, just change the...
Found in a Philips' 1968 documentation, this circuit is slightly different from the previous one. The...