# Voltage reduction issues in an existing circuit [closed]

In the above diagram, I am trying to reduce the input voltage of 7.4v to no more than 3v, which is the maximum rating for the M2 motor. This is for a boxmag used with an Airsoft gun, specifically an M16 style 5,000 round boxmag. The idea is to operate the gun and the boxmag off the trigger switch of the gun. I have had this circuit in use in other boxmags, but recent events has shown that a potential problem with overheating of the resistor can occur and thus result in frying the resistor.

My current components are listed below, Motor (M2) Diode (1N4001) (Had to replace the original Schottky diode) Resistor 5 ohm, 1/2 Watt, 5% tolerance Switch DPDT

The switch must be able to achieve two modes of operation, 1] constant power for priming the boxmag, and 2] selective power for operation off the gun's trigger switch. The diode acts as a control gate to prevent damage to the motor, or that is how I understand it anyways.

I ran some calculations using available data to determine the resistor's rating, these are the calculations below,

The motor has these statistics, Voltage range: 1.5 to 3 volts Current: 0.18 to 0.25 amps w/o load, 0.70 amps +/- 15% at max efficiency Output: 0.31 watts

If I understood everything correctly, the device (M2) has a resistance of 10.57 ohms, which when entered into the formulas and calculated out, should have brought me to 2.37 volts at the motor, but since the circuit keeps frying the resistor, I'm not so sure anymore.

Therefore, my question is, how can I address this issue such that I will achieve the correct results without risking frying the resistor?

Any assistance to achieve my goals is appreciated. Thank you.

## closed as unclear what you're asking by Olin Lathrop, PeterJ, Daniel Grillo, dim, Dmitry GrigoryevJun 24 '16 at 13:02

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• Stack exchange doesn't use PHPbb type markup, there's a button with an image insert (or Ctrl-G) where you can upload an image from your PC if you want to edit your question. I was about to try editing it but the Photobucket links don't seem to be working. – PeterJ Jun 24 '16 at 10:18
• Those links don't work so we can't tell what is being asked. Closing. – Olin Lathrop Jun 24 '16 at 10:55
• Sorry, didn't know how that worked, most forum sites I'm familiar with do not have a direct upload ability. I have fixed the issue and added some additional information, please release my hold status. Thank you. – BoogerMc Jun 24 '16 at 15:03