Tapping Key Physics Lab
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Product Code : SCL-EAE-12118
Tapping Key Physics Lab (SKU SCL-EAE-12118) is a momentary, normally-open switch that closes a circuit only while its knob is pressed and springs open the moment it is released. It lets students send brief pulses of current through galvanometers, bridges and coils in school and college physics practicals, protecting sensitive meters and saving cells. Science Lab Supplies manufactures the key in Saha, Ambala, India, at Plot 448, HSIIDC Industrial Area, and supplies it without intermediaries to schools, colleges, tender contractors and distributors.
Specifications
All specifications are given row by row in the table below. In short, a brass leaf spring with brass contacts is mounted on an insulating polymer or ebonite base, with an insulating finger knob and two 4 mm nickel-plated brass binding posts, rated for low-voltage circuits up to 24 V DC and 2 A.
| Specification | Value |
|---|---|
| SKU | SCL-EAE-12118 |
| Switch action | Momentary, normally-open (NO), single tapping key |
| Base material | High-density insulating polymer / ebonite |
| Contact material | Brass |
| Spring | Brass leaf spring strip, self-returning |
| Press button | Insulating finger knob |
| Terminals | 2 x 4 mm nickel-plated brass binding posts |
| Accepted connections | Banana plugs, spade lugs or bare wire |
| Maximum voltage | 24 V DC |
| Maximum current | 2 A |
| Documentation | Instruction leaflet with wiring diagrams |
| Manufacturer | Science Lab Supplies, Saha, Ambala, Haryana |
| Country of origin | India |
Applications and Experiments for the Tapping Key
Wired in series, the key lets current flow only for the instant it is pressed. That makes it the standard way to apply a brief pulse to a sensitive meter or coil and to check for deflection without leaving a circuit on, a routine need in electricity and magnetism practicals.
- B.Sc. physics: charge and capacitance measurements with the Ballistic Galvanometer, where a short tap gives a clean throw.
- Class 12 physics: checking balance on the Meter Bridge or Wheatstone Bridge without continuous current heating the wire.
- Electromagnetic induction: switching short pulses through Induction Coils with Cores to observe induced current.
- Potentiometer balancing and general protection of galvanometers and ammeters.
The key is for low-voltage DC circuits only; never connect it to mains, and stay within 24 V DC and 2 A to avoid arcing and pitted contacts.
Standard Scope of Supply
Every Tapping Key Physics Lab is supplied as one key unit with its binding posts already mounted, together with an instruction leaflet showing elementary circuit wiring diagrams. Connecting leads, cells and meters are not part of the key and can be quoted alongside it.
Packing, MOQ and Lead Time
You may request a price for one key or for enough to fit out every electricity bench in a school or college lab. The quotation itemises packing, delivery time and price for your quantity, and matching plug keys, galvanometers or bridges can be included as further lines.
Science Lab Supplies has an Importer-Exporter Code and can ship to buyers in Malaysia, Peru, Egypt, Iraq, Nigeria and Kenya. Contact the team through the contact page or the enquiry cart; buyers working to a tender will find details on the lab tender page.
Frequently Asked Questions
How does a tapping key protect a galvanometer?
Current flows only while the knob is held down, so students can tap briefly to see the direction and size of a deflection before closing the circuit for longer, and the meter is never left under sustained current.
Can the tapping key be used on mains electricity?
No. It is built for low-voltage educational circuits up to 24 V DC and 2 A, and must never be connected to an AC mains supply.
What can be connected to the terminals?
The two 4 mm nickel-plated brass binding posts accept standard banana plugs, spade lugs or bare hook-up wire, so the key fits into existing school circuit kits without adapters.
Is Science Lab Supplies the manufacturer or a trader?
The tapping key is produced by Science Lab Supplies in its own manufacturing unit at Saha, Ambala, India. You are buying from the factory, and the quotation you receive is issued there.
Related Keys, Jockeys and Bridge Apparatus
These keys and instruments complete the circuits a tapping key is used in: other switches for making, routing or reversing current, a jockey for bridge wires, and the meters and resistance networks being protected. They are from the Electrical and Electronics and Lab Meters ranges and can be quoted together.
- Brass One Way Plug Key — brass plug key that makes or breaks one circuit path.
- Reversing Key Commutator For Lab — reverses current direction, rated 24 V and 3 A.
- Brass Four Way Plug Key — brass blocks on a Bakelite base with two plugs, up to 5 A.
- Brass Two Way Plug Key Switch — three-block key routing current to one of two branches.
- Pencil Jockey for lab — brass knife-edge probe with a 4 mm socket for bridge wires.
- Post Office Box Plug Type — resistance box with two spring keys for battery and galvanometer.
- Galvanometer — centre-zero −500–0–500 µA demonstration meter.
Browse the full Electrical and Electronics range, the Lab Meters range for galvanometers and meters, or all physics lab equipment.
Last updated: 9 October 2026
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