We found this circuit generates signals from 200 Hz to 62 kHz and can be used to repel mosquitoes and mosquitoes. The circuit can be powered from 2 small batteries to 9 V battery.
This circuit uses a ceramic transducer to emit ultrasound whose frequency depends on C2. The...
We found this Nicad cell charging circuit in an English publication from the 1970s. The circuit can...
This small transistor radio was published in Radio Electronics magazine in November 1957. The...