PURPOSE: To show the RC time constant.
DESCRIPTION: A small circuit contains a series capacitor and a variable potentiometer. In parallel with the cap is a neon flash lamp that will discharge the cap when the charge in it has reached 90 volts. A 90 volt radio battery supplies the power. Vary the pot to change the flash rate. Observe the voltage trace on the computer with the Pasco Science workshop interface.
EQUIPMENT: The Neon relaxation oscillator and battery are stored in the electricity and magnetism cabinets. The science workshop is stored in the vault.
SETUP NOTES: In the science workshop use the file called rc to obtain the digital oscilloscope with the correct time base and volts scale to see the waveform.
Updated by Jun Qi in 3/13/2000