Planck's Constant Apparatus
Product Code : JLI-PLE-10567
Quick Answer: The Planck’s Constant Apparatus is a ready-built photoelectric circuit with a caesium antimony photocell, a variable retarding voltage and a 0–19.99 V LED voltmeter. Six coloured narrow-band filters vary the light frequency, and a 4 mm to UHF lead connects it to a picoammeter.
Last updated: 18 October 2026
Key Features
- Caesium antimony cathode photocell with a spectral response of 185–650 nm.
- Retarding (stopping) voltage set by a 10-turn potentiometer and shown on a 0–19.99 V LED display.
- Six narrow-band coloured filters change the light frequency.
- Female UHF socket and a 4 mm to UHF lead for connecting a picoammeter.
- Runs on a 9 V PP3 battery.
Technical Specifications
| Specification | Value |
|---|---|
| Photocell | Caesium antimony cathode, 185–650 nm spectral response |
| Stopping potential control | 10-turn potentiometer |
| Voltmeter | 0–19.99 V DC, LED display |
| Filters | 6 narrow-band, FWHM bandwidth 4–15 nm |
| Picoammeter connection | Female UHF socket; 4 mm to UHF lead included |
| Power source | 9 V PP3 battery |
| Dimensions (W x H x D) | 205 x 150 x 115 mm |
How It Is Used
Light through each filter falls on the photocell, and the retarding voltage is raised until the photocurrent on the picoammeter drops to zero. Plotting this stopping potential against the light frequency for the six filters gives a straight line from which Planck's constant is calculated.
Frequently Asked Questions
What else is needed with the Planck’s Constant Apparatus?
A picoammeter, such as the JLab India picoammeter, to read the photocurrent. The apparatus has a female UHF socket and comes with a 4 mm to UHF lead; it runs on a 9 V PP3 battery.
How is the light frequency changed on the Planck’s Constant Apparatus?
Six coloured narrow-band filters, with an FWHM bandwidth of 4–15 nm, are provided to vary the frequency of the light reaching the photocell.
Related Physics Lab Equipment
See the full physics lab equipment range, or these related modern physics apparatus:
- Plancks Constant Determination Box
- LED Characteristics Apparatus
- Energy Band Gap Apparatus
- LDR Characteristics Apparatus
Export orders for the Planck’s Constant Apparatus are accepted from schools, colleges and distributors in Senegal, Indonesia, Kazakhstan, Burkina Faso, Kiribati and Georgia.
For a quotation on the Planck’s Constant Apparatus, contact JLab India on +91-8569909696.
