The square card with two chips is the transmitter (powered by 9V).  The longest card is the output and you can connect it to the part of your project that needs power.

Inductive load is a means of powering a device without a direct wire connection. Most people have discovered the inductive charge with a rechargeable electric toothbrush: you may have noticed that you recharge it by placing it in the holder, but there is no direct plug. These chargers operate by taking a power transformer and dividing it in half, an AC waveform is generated in one, and torque in the second coil.

This is a basic charger, and it works, providing a 5V DC output from the output half when the input half is powered with 9V to 12VDC. You can consume up to ~500mA if the coils are spaced 2 or 3 mm apart. If you only need 100 or 200mA, you can be 7mm apart. For a 10mA print run, the coils can be spaced half an inch (12.5mm) apart. Any non-ferrous/non-conductive material (air, wood, leather, plastic, paper, glass) can be used between the two coils. The material does not affect distance or efficiency. The coils must be coaxial enough, try to obtain that they are parallel and that the circles are aligned to obtain the best transfer of power. (This is why the electric toothbrush must fit into the plastic holder, it aligns the two coils for better efficiency).

Because it is an air transformer, it is quite inefficient. Only about 40% of the energy consumed is at the other end, but for low power or load projects. If you pull 5V 100mA on the output side (0.5W), you will need 0.5W * 2.5 / 9V = ~150mA on the input side. The idle current is about 70 mA at all times, even when the other coil is not nearby.

These are basic modules, probably used for a cheap toy. We do not have data sheets or specifications for them. We see a feedback resistor divider on the output side using 0603 SMT resistors so that an advanced user can weld into different values to transform it into a 3.3V output.

Features

• Coil thickness: 1.75mm / 0.07"
• PCB thickness (at tallest point): 3mm /  0.12"
• Receiver weight: 5.5g
• Transmitter weight 5.7g