Lightning Detector Circuits

Summary

+ New Lightning Detector (Also see magnetic antenna version , op-amp version and Compound Transistor version) Also: Original Lightning Detector Page To observe the lightning strikes on a map in near real time try: https://www.iweathernet.com/lightning/latest-lightning-strikes-on-google-maps The latency is usually under 10 seconds but that's long enough to make correlation with a flash from your detector with a flash on the map a bit challenging. Built to make the wiring easy to follow, but I prefer this circuit to the original. Read the text below. This new lightning detector circuit uses a single inductor tuned circuit to receive static pulses from lightning at a frequency near 200 kHz. The need for a tapped tuned circuit is eliminated by employing a very high input impedance RF amplifier that uses a darlington transistor. The amplifier is micro-power and the whole circuit draws only about 200 uA from two alkaline D cells, hardly denting the shelf life. The flasher portion of the circuit is similar to the earlier versions only the polarity of the transistors is reversed. As a result the output pulses momentarily go to ground from a normally-high state. The schematic and close-up photos were made with the beginner in mind. Questions about the schematic can be answered by close-up examination of the photos. Try a magnifier utility for an even closer look. The 150k resistor in the base of the 2N4401 may be replaced with a series combination of a 100k resistor and a 100k (or greater) potentiometer to add sensitivity control. Simply adjust the potentiometer until flashing just stops for maximum sensitivity. The fixed resistor is plenty sensitive for most users. But, the receiver will only work well outside or near a window. A few yards of wire could be used to run an antenna out a window but connect a 47 pF capacitor in series with the wire at the detector end. Also, connecting a good ground will improve the sensitivity. Keep the unit away from electronic or electrical ...