This simple low power triplicator was found in 90’s American documentation. The diodes can be general purpose types and the frequency is determined by the RC network of the 555.
The integrated circuit of this amplifier is not very common today. The output transistors can be...
This circuit produces a loud sound in the speaker when water level reaches the sensor. The power...
This circuit was found in a Linear Technology documentation from the 90's. The integrated circuits are...