Working with tube gear and high-end audio equipment presents certain challenges, the most significant being the involvement of high voltages and large storage capacitors. These two factors combined create a risk of electrical shock, as capacitors do not immediately discharge after powering down the equipment.

Most technicians and hobbyists are aware that capacitors should be discharged before coming into contact with them. While many still use the traditional method of shorting capacitors with a screwdriver, this can damage both the capacitor and the screwdriver—though the sparks may be amusing to watch!

Typically, a resistor is used to safely discharge the capacitors, but I wanted something more reliable and precise. That’s what led to this project. My solution safely discharges capacitors, regardless of polarity, and provides a visual indication throughout the discharge process.

Be sure to watch the video on the project, and read its description (show more), for further details:

https://youtu.be/7PvvOBByOXk