Miniature Frequency Probe measures 1Hz to 5MHz

https://www.electronics-lab.com/miniature-frequency-probe-measures-1hz-to-5mhz/

David Johnson-Davies shared another great and mini project on his blog. He writes: The Frequency Probe is a handheld tool designed to help you debug your circuits by giving a visual indication of the frequency or voltage at the probe. For a periodic waveform it gives a digital readout of the frequency, with a range […]