Philips - GM 2317 Audio testing equipment

This is a Philips GM2317: an old low-frequency generator / sine generator from the 1950s.

It was used to generate a variable test signal, for example for checking and calibrating:

- radios
- amplifiers
- speaker and audio circuits
- measuring equipment

The generator provides a sinusoidal signal from about 20 Hz to 250 kHz. The large circular dial in the middle sets the frequency; with the knobs on the right you adjust the output voltage.

Nice old Philips measuring instrument — fairly sturdy and nowadays mainly interesting for vintage electronics enthusiasts.