Found in a 1947 publication, this 7-tube amplifier uses four tubes in the output stage. The circuit uses a power source with a transformer.
This circuit was found in a French publication in 1981, but it can still be assembled with only...
We found this circuit in an Argentine publication from the 1970s. The circuit can be used to...
This sophisticated repellent uses a double 555. We find it in an American documentation from the...