This circuit allows you to read resistors up to 20 M ohms, converting it into voltage. The circuit is from the 90s. The operational ones used admit modern equivalents.
This circuit can be used as a control shield for microcontrollers of all types. The supply is made...
The figure below shows an AC transconductance amplifier with the National Semiconductor LM3900. The...
This circuit provides a good audio power from a signal at least 1 V of amplitude. The MOSFET must...