Magnetic Levitation

Magnetic Levitation Parts List

A detailed list of electronic components is shown below. For parts availability and places to buy them, you can read about buying the parts.


Resistors listed in order by value are 1/4-watt, 5% unless otherwise indicated.

300 ohms R11
500 ohms R2
1,000 ohms R1, R12, R13, R14 
1,500 ohms R10
10,000 ohms R4
11,000 ohms R6
22,000 ohms R8
56,000 ohms R3
100,000 ohms R5
150,000 ohms R7
370,000 ohms R9
50K linear taper VR1 (and VR2 opt.)


C1,C2  47 uF electrolytic
C3 0.1 uF ceramic or tantalum (must not be electrolytic)


Q1,Q2 OP505A infrared photo detector, or equivalent
Q3 2N3055 NPN power transistor
LED1,2,4  Red light-emitting diode
LED 3 Infrared LED emitter
IC1-4 LM741 op amp, Radio Shack 276-007
D1 1N4001 (or 1N4004) silicon diode, 50v (or more) peak inverse voltage


+/- 15 vdc power supply, 1 amp
9 vdc power supply, 1 amp
Breadboard wiring pad (or printed circuit board by Amadeus)
18-ga stranded wire for power
Solid hook-up wire
24-ga (or thicker) magnet wire for lifting coil
6-terminal barrier strip (2 ea.)
Wood for base and frame

Alternatives for the LM741 Op-Amp

I chose the LM741 op-amp out of nostalgia and convenience. It was an extremely successful and common op-amp about twenty years ago.

There are lots of modern choices for dual- and quad-package op-amps. By using a package with multiple op-amps, you can reduce the number of parts and lower the cost. For example, you could use a single quad-package op-amp instead of four separate 741s. This would allow a very small printed circuit board to contain all the electronics!

Different packages also provide improved parameters such as noise immunity, speed, power, etc. Here are several good choices recommended by David at All these are better in every parameter than the trustworthy but ancient LM741.

These parts are commonly available on-line suppliers such as Digikey or Future-Active.

  National Semiconductor Maxim Integrated Circuits Analog Devices
Duals LF353, LF412 MAX412 OP270, OP271, OP249
Quads LF347 MAX414 OP470, OP471
Instrumentation amp     AD620, AMP02
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