Wireless Ammeter Sensor Redy

Quick Answer: The Redy wireless ammeter sensor measures the electric current flowing through it and transmits the readings wirelessly, so current can be graphed against time or voltage. Like any ammeter, the wireless ammeter sensor is connected in series within a low-voltage teaching circuit.

Current Logged, Not Just Read

A moving-coil or digital ammeter shows current at one instant; this sensor records it continuously, and that changes what students can investigate. Charging a capacitor through a resistor becomes a smooth, decaying current curve; the brief surge as a filament lamp is switched on, while its cold filament still has low resistance, is captured rather than missed; and the current through a thermistor can be followed as it warms.

The sensor must sit in series, so the whole current passes through it. Connecting it directly across a cell or power supply, as a voltmeter would be, places almost no resistance across the supply and can damage the sensor or the supply. The title does not state the current range or maximum voltage, so check both before use and keep to low-voltage circuits.

For energy and power rather than current alone, the wireless joulemeter sensor records the energy delivered to a component over time.

Specifications

Applications

• Ohm’s law and the current and voltage characteristics of resistors, lamps and diodes
• Comparing current in series and parallel branches
• Capacitor charging and discharging through a resistor
• Switch-on current surge in a filament lamp
• Current drawn by a small motor under changing load

Care & Handling

• Always connect the sensor in series and check the circuit before switching on.
• Start with enough resistance in the circuit to keep current within the rated range.
• Never connect it to mains electricity or to supplies above its stated voltage.
• Switch off the supply before changing connections.

Why Choose LabEquip

Physics teachers running electricity practicals with data-loggers, and electronics students studying transients, are the usual buyers. LabEquip places this sensor within its chemistry lab equipment; for current range and leads, get in touch on the contact page.

Frequently Asked Questions

Why must an ammeter be connected in series?

Current is the flow of charge along a path, so the meter must be part of that path to measure all of it. An ammeter has very low resistance, so connecting it in parallel would short-circuit the component or supply.

Can the sensor measure current in both directions?

Many data-logging current sensors show positive and negative values for the two directions of flow, which is useful for capacitor discharge. Check how this sensor reports reversed current before relying on it.

How is Ohm’s law investigated with the ammeter sensor?

Place the sensor in series with a resistor, measure the voltage across the resistor with a voltmeter or voltage sensor, and vary the supply in steps. A straight line through the origin on a current against voltage graph shows the resistor obeys Ohm’s law.

Why does a lamp draw more current when first switched on?

A cold tungsten filament has much lower resistance than a hot one, so current is high for a brief moment and then falls as the filament heats. A logging sensor shows this as a sharp spike.

Is it safe to use with mains-powered equipment?

No. It is intended for low-voltage teaching circuits powered by cells or bench supplies. Never connect it to mains wiring or to equipment plugged into the mains.

What should I check if the reading stays at zero?

Check that the circuit is complete, the supply is on and the sensor is in series rather than across a component. A blown protective fuse, if the sensor has one, can also stop it reading.

Last Updated: September 2026