We found this circuit in an old Radio Electronics. The transistors can be the BC548. The circuit tests signals of up to a few megahertz giving the status indication on an LED.
![](/images/stories/cir/225212522023_173252_0001.gif)
We found this circuit in an old Radio Electronics. The transistors can be the BC548. The circuit tests signals of up to a few megahertz giving the status indication on an LED.