This circuit for dual-gate MOSFET was found in a 90’s Popular Electronics. The coils are according to the frequency range that must be amplified.
This circuit activates a relay when the water reaches the sensors. The circuit is from a magazine...
The noise comes from the PN junction of a common silicon diode. Since no gain is given by the...
We have here an interesting audio preamplifier, which can be useful to those who are looking to...