I am new to electrical circuits and created the following circuit using falstad: circuit

With a 9V battery, what is the least resistance (instead of the 220k resistor) required to:

  • Complete the circuit
  • Not damage the battery and extend its life as much as possible
  • 100% safe in the sense that even if uninsulated wires used and touched, no harm will be caused regardless of the length of time of contact

I understand that typical batteries use DC. I was looking at Cahier technique no . 172 Earthing systems in which had figure 1 depicting the safety of amps with respect to time. Unfortunately it is based on AC not DC. Any help would be appreciated!

  • 5
    \$\begingroup\$ A battery with a resistor is just a battery discharging device, or a heater. Please edit your question to describe what you're really trying to accomplish. Is this for education? Heating? What? Old-technology 9V dry cell batteries could be safely shorted, because they were much better at dissipating heat than they were at generating current. A "9V" battery with alkaline or NiMH cells may actually manage to heat #24 wire up to the point where the insulation burns. \$\endgroup\$
    – TimWescott
    Jun 24 at 14:47

1 Answer 1


9V Alkaline batteries are safe even if shorted unlike Li Ion Cells, and will discharge rapidly to get warm or even hot. That damages the battery, so the longest life is the highest resistance and the shortest life is the lowest. Use the power and current charts for reasonable solutions for the short term and long term.

enter image description here https://www.digikey.in/en/products/detail/duracell-industrial-operations-inc/9V-MN1604/13280363


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