This circuit can detect static charges or extremely low voltages. The circuit was found in ancient American documentation and makes use of a JFET. A BF245 which is a more modern transistor can be used.
This amplifier can work with voltages between 12 and 22 V. This means that we can use it in the...
When pressing S1, S2 or S3 this circuit generates different tones for a tone-modulated...
The configuration shown in the figure uses two NPN transistors activating the load when the input...