An Open Hardware, low-noise, oscilloscope power rail probe. It allows you to measure millivolt-level ripple on a power rail up to 20V, using a normal oscilloscope. Commercial versions of this product cost upwards of £4,850!
The probe accepts a connection from a power rail under test, via a 50-ohm cable. AC is passed, and an adjustable offset is applied to the DC voltage. Your oscilloscope sees 0V DC, allowing power supply ripple and transients to be viewed in high resolution.
- Open Hardware, made in the UK. Schematics and design files are freely available.
- Max voltage offset ±20V
- Input impedance 50kΩ (0 - 30kHz) / 50Ω (30kHz - 1GHz)
- Average signal attenuation of 1:1.15 (approx. -0.5 dB) * Noise <500 µVp-p over full bandwidth
- Active signal range ±1V
- Isolation between chassis/USB and BNC test connectors
- Battery powered to minimise noise
- Li-Ion 18650 batteries rechargeable via USB-C connector
- 9V+ USB-PD supply required - most laptop power supplies are compatible - or alternatively 12V DC barrel jack
The probe should be connected to an oscilloscope set to 50-ohm input impedance, and works best with inputs <1-ohm impedance.
What's included?
Assembled probe
- 1x finished power rail probe, ready to use.
No cables are included. You will need to supply your own USB-C power cable and USB-C power supply capable of 9V USB-C PD (eg, a laptop power supply).
Alternatively, you can tick the box to include a USB-C cable and compatible UK power supply.
Assembled probe + cable kit
- 1x finished power rail probe, ready to use.
- 2x 3 metre coaxial cables (SMA male - SMA male)
- 4x SMA female - BNC male adapters
PCB and enclosure option
If you select this option, you'll receive an unpopulated PCB, aluminium enclosure, the machined front and back panels + bolts. You'll need to purchase the components and assemble the board yourself (see GitHub for a BOM & schematic).
This product must be shipped via DHL, due to the internal batteries.