Sound

This superb, robustly built mini digital sound level meter has a wide dynamic range and gives virtually instant readings. It is ideal for quick and easy sound level checks. • Single Measurement Range: 30 to 130 dB • Temperature Range: -20 to +70 °C • 0.1 dB Resolution • Fast 125 ms, or Slow 1 s time response weighting • Precision ½ inch electret condenser microphone • Lmax (LAFmax, LASmax) • Lmin (LAFMin LASmin) • 30 mm Colour backlight LCD display with function indicators • Display updates every 300 ms • Data hold displays highest or lowest measured valve • Low battery indicator and auto power off after 15 minutes of no activity (can be user disabled) • Supplied with wind muffler and batteries (3 x AAA) • Dimensions: 144 x 56 x 31 mm, Weight: 73 g

A compact loudspeaker unit fitted with 10 watt, 8Ω driver. Connection is via colour coded 4 mm sockets. Fitted into durable ABS case.

This speaker is well suited to laboratory demonstrations using sound. It comprises 10 W RMS (20 W PMPO) 8 Ω impedance speaker in robust beech wood and acrylic frame, with 4 mm sockets mounted on the front. The design means that the loudspeaker can be used in either a vertical or horizontal position. Speaker diameter: 125 mm. Dimensions: 225 x 175 x 100 mm.

The small size of this microphone makes it ideal for experiments with sound interference. Other typical applications are measurement of sound frequencies, speed of sound experiments and the recording of sound by data loggers. The microphone is supplied with a one metre cable which connects directly to the electronic counter TI68730 or timer FO140110. It can be connected to an oscilloscope or other measuring instruments via power supply HE110105. Supplied with 10 mm diameter support rod. Dimensions (L x Dia.): 105 x 30 mm.

A hollow wooden sounding box with scales divided in mm between fixed bridges over which three wires are stretched. To one wire, spring balance reading to 100 x5 N is fitted and the tension exerted and measured can be finely adjusted by a wing-nut. Another wire passes over a pulley and can be loaded as desired. A third wire is provided for comparison, its tension may be adjusted by means of a wrest-pin The distance between the fixed bridges is 72 cm. Complete with three movable bridges, wrest-pin key and a set of steel wires, length 1.5 m of 22, 24, and 26 SWG. The pack of replacement wires, sold separately, has steel and brass wires, each in 22, 24, and 26 SWG. Dimensions (L x W x H): 129 x 13 x 11 cm.

An improved version of the classic Bell in Jar experiment. The base is fitted with rubber sheet which ensures a good seal between the jar and pump plate, without the need for vacuum grease. The pump plate is lightweight aluminium, mounted on a heavy tripod base, with a tube connection to the central pillar to evacuate air from the bell jar on top. A stopcock allows the chamber to be sealed, allowing the vacuum to be kept when turning off the pump. The bell jar is robust acrylic which is safe in the event of implosion, and has flat flange to ensure good seal with the pump plate. The bell is suspended by wires to reduce conduction of sound to the bell jar. Connection is by 4 mm sockets on the top bung. The bell can be heard getting quieter as the air is evacuated. Then, by closing the tap, turning off and disconnecting the pump, and then slowly allowing the air back in, the bell can be heard getting louder, as air is required to conduct the sound. The high-quality bell operates on 4-6 V DC or AC. Requires suitable vacuum pump, and heavy-walled vacuum/pressure tubing. Dimensions: Bell Jar • Height 260 mm to neck • Internal diameter 140 mm • External diameter flange 180 mm Pump Plate • Height 195 mm • Diameter 250 mm

Pump plate for SO180500.

Bell jar for SO180500.

An effective and compact alternative to the traditional Bell in a Jar apparatus. Comprising a strong acrylic vessel, with a simple buzzer circuit. The vessel has an outlet through which air can be evacuated using a vacuum pump (not included). The buzzer is mounted on foam to reduce transmission of sound to the vessel walls. When the air is evacuated, the sound of the buzzer is attenuated, as there is no air through which the sound is transmitted to the walls of the vessel. Dimensions (H x dia): 140 x 100 mm

For use with a standard bell jar for demonstration experiments involving low pressure. The plate is made of PVC and has a vacuum connection fitting with valve and thumb screw for the return air. Two standard 4 mm jack connectors are provided with 4 mm jack connectors available inside the jar. Tube Dimensions (Dia.): 10 mm. Plate Dimensions (Dia.): 210 mm. • For use with 150 mm diameter bell jars only

A crystal microphone giving 10-20 mV output without batteries. Used for displaying students' voices on sensitive oscilloscope, or for speed of sound experiments. Fitted with mm colour coded sockets. • Frequency range: 100-10,000 Hz • Impedance: 200 Ω • Sensitivity: mV/Pa/kHz

This 4W, 8 Ohm Mylar-cone loudspeaker comes mounted on an acrylic base, so that it can be used either vertically or horizontally. The front of the speaker has a hard protective cover with drilled holes. Dimensions (Speaker Dia.): 60 mm. Overall Dimensions (H x W x D): 120 x 90 x 40 mm.

This Sonometer pickup contains a single guitar-type magnetic pickup. When placed under a moving steel wire, such as on Sonometer, an emf is induced in the pickup which can be displayed on an oscilloscope. Period, frequency and amplitude measurements can then be taken from the oscilloscope screen. The whole unit, constructed in clear acrylic, measures approximately 90 x 40 x 20 mm and comes with integral 4 mm sockets and instructions for use.

Aluminium. Boxed set of 8. Range C.256 Hz to C512 Hz.

This multi-purpose microphone has been designed for a number of applications and experiments requiring the use and demonstration of audio input, including voice and music waveforms. The electret condenser type microphone is mounted in a moulded plastic box with two standard 4 mm output connectors, an on/off switch and a power indicator. • Electrical Supply: 9V PP3 battery (supplied) • Dimensions: 68 x 120 x 36 mm • Mass: 0.15 kg • Sensitivity: -42 db • Frequency Response: 20 Hz to 20 kHz • Output Impedance: 2.2 kohm

Frederiksen Microphone Psu