This signal injector circuit, an astable multivibrator, was found in a 1971 magazine. The circuit can still be mounted with BC558 transistors. Power can be supplied with voltages between 6 and 9 V.
![](/images/stories/cir/205012502023_150350_0001.png)
This signal injector circuit, an astable multivibrator, was found in a 1971 magazine. The circuit can still be mounted with BC558 transistors. Power can be supplied with voltages between 6 and 9 V.