# How many Amperes to kill fruit flies and mosquitoes?

As above. Making a homemade trap to kill them all.

• If you were to presume that the resistance of the arthropod is about 1000 ohms, then it'd require about 2 amperes. Jul 10 '16 at 12:44
• I have this bug-zapper in the form of a tennisracket. It takes only two AA batteries of 1,5 Volt. It is succesfull in killing mosquitoes but often fails at big flies.
– RHA
Jul 11 '16 at 18:46
• It's not the Amps that matter, it's the voltage. humans are safe up to about 80V DC. 4V is like moving energy in a slow train, 1000v is like moving energy in a bullet. Therefore, 1000V also can arc more easily through the air. If you use 240V at 0.1 amps, that's 24W it's probably quite enough to kill a mosquito. A 200W source in 4V will not hurt a human, but in 3000V it will kill him easily. I can't confirm that 20W at 300V is not dangerous to a human. You will probably find yourself using an CC Constant Current supplying about 10W at a low voltage and upping the voltage a bit to zap the moz. Sep 3 '17 at 19:49
• Current kills. Voltage is potential difference. Sep 4 '17 at 2:35

I am not an electrician and may not be the right person to answer this. But I recently read this paper (Keller et al., 2016) and maybe this helps ... Keller et al. (2016) have a look at laser induced mortality in mosquitoes. It might not be fully adaptable to your needs (there is not much context in your question, though; I have no idea what kind of trap you are trying to build ... if it's going to be a fancy laser trap, the cited paper will be your perfect guide through the building process - however, you have to figure out the automatic camera detection (they are planning that, too) for yourself as they have not published that, yet).

Now, giving a concrete answer: Keller et al., (2016) found that lasers with 0.5W to 4W are sufficient for efficient mosquito inactivation. If you are planning to use a plug bucket (230V) this would be (0.5W/230V=) 0.002A to (4W/230V=) 0.017A. You could also set this up with a 9V battery. With a 4W laser this would be (4W/9V=) 0.44A. Using a lithium-based battery this would last for about (1000mAh/(4W/9V=0.44A)=1Ah/0.44A=) 2.27h total laser time.

I do not know if this easily translates to electric current, though ...

• What did Keller et. al. use as the ohms of the insects in their investigation? Jul 10 '16 at 12:44
• They did not assume any. They tried this with a variety of powers and pulse lengths and then measured mortality rates. Jul 10 '16 at 17:05
• Sorry, laser's not applicable. The trap's made up of loads of exposed wires alternating between live and ground over a food source, waiting for a fly/mosquito to close the circuit to (hopefully) fry them. Not going to plug it into the mains, though. Too dangerous. Thanks for the power details. Jul 11 '16 at 18:07
• @user3635998: Ah, ok. Maybe you should have a look at how these electric fly flaps work, I think they are powered with two AA batteries and get up to 1000V with a voltage converter. Jul 11 '16 at 18:26

there's an electronics topic for that, it states: Most flyswatters conform to electrical safety standards for humans: a limit on the charge stored in the capacitor. A discharge of less than 45 µC is considered safe, even in the unlikely scenario that the current from a flyswatter would be flowing from one arm to the other arm, partly through the heart.1 This means that the capacitor of a 1000 V flyswatter should be less than 45 nF. Due to this precaution for humans the initial shock is usually inadequate to kill flies. a limit on the current after the initial discharge. The maximal continuous current of most flyswatters is less than 5 mA. This current is safe, even when flowing from one arm to the other arm

there is a slow mo zapper here. https://www.youtube.com/watch?v=oUJLgKkmllA