Tools · MuTech Robotics

Resistor colour code

Band 1

Band 2

Multiplier

Tolerance

220 Ω ±5%

Supply voltage (V)

LED colour

Current (mA)

220 ΩUse the standard value · Calculated: 200 Ω · 41 mW

Fill in any two boxes and leave the others empty.

Voltage (V)

Current (A)

Resistance (Ω)

Power (W)

24 W12 V · 2 A · 6 Ω

Cell type

Capacity of one cell (mAh)

Cells in series

Cells in parallel

Your circuit draws (mA)

7.4 V · 2000 mAh14.8 Wh · Run time: 3 h 12 min

Assumes 80% of the capacity is usable. Cold weather, old cells and motors starting up all shorten this.

Output you want (V)

R1 (Ω)

Input voltage (V)

Load current (mA)

Use R2 680 Ωgives 4.79 V · Heat in the regulator: 2.16 W

Fit a heat sink.

Number of servos

Servo type

Your 5V supply (A)

2.8 APossible peak draw · Your supply has enough headroom.

Rough stall-current estimates. Real servos vary; check your servo's datasheet.

Weight to lift (g)

Arm length (cm)

Weight of the arm itself (g)

Safety margin

4.5 kg·cmtorque needed · 0.44 N·m

Smallest servo that fits: Standard metal-gear servo (about 10 kg·cm)

Holding the arm straight out is the worst case. Check the rating of your own servo.