A power electronic switch-mode three-leg converter is a flexible converter and hence very useful for practical teaching of several disciplines within electric power engineering. It can be used as a half-bridge, full-bridge and three-phase converter, to mention a few, and enables the user to study many different power electronic topologies. The converter, controlled by a microcontroller, can also be used for teaching digital control of power electronics. Its output can be varied in frequency, magnitude and waveforms, and can also be measured by the microcontroller. The flexibility of the converter makes it possible to utilize it in drive circuits for a wide range of loads and can therefore also be used for teaching electric drive systems.This thesis shows a solution of how to design the switch-mode three-leg power electronic converter. The converter is designed and implemented on a printed circuit board (PCB) together with other necessary components. To meet the safety requirements of the problem description, the power rating is low, 12 A * 50 V, and the power circuit is isolated from the microcontroller on the PCB. The microcontroller chosen is the Texas Instruments PiccoloTM ControlCARD and pulse-width modulation and analog-to-digital conversion is implemented with real-time programming.This system developed is verified, except for the MOSFET drivers and measurement circuits. As time was limited, the laboratory work had to be ended in favor of writing the report. Unfortunately, this made it impossible to test the full system setup. A full description of the changes to be implemented for the whole system to be functioning and further tested is provided.A system for using the converter designed in a DC motor drive, by utilizing two of the bridge-legs as a full-bridge converter, is studied. The programming code is tailored for the specific purpose and speed measurements and control algorithms were added. Due to the converter not functioning, the testing of the DC motor drive could not be performed. However, full planning and controller implementation was done.