PVF2A204A1AR03 Datasheet PVF2A204A1AR03 | P1-P2

APPLICATION NOTE

Improving Hearing Aid Performance

with Bourns® Trimpot Trimming Potentiometers

05/18 • e/T1812

3312

INTRODUCTION

Figure 1. Functional Block Diagram of a Hearing Aid

Microphone

Incoming

Signal

Resulting

Signal

Resulting

Signal

Receiver

(Earphone)

Outgoing Signal in

Acoustical Form

Filter Amplier

Hearing aids are devices that amplify sound for people who have hearing impairments. Sound is

converted to an electrical signal, amplied and then reconverted to acoustic energy in the inner ear.

Hearing aids can be small enough to t behind the earlobe or within the ear canal. e level of

amplication that a person needs will determine the operating range of the hearing aid.

SYSTEM COMPONENTS:

• Microphone – converts acoustic energy to electrical energy

• Amplier – makes the sound louder by increasing the electrical signal strength;

maintains the frequency response of the microphone

• Volume (Gain) Control – controls the overall signal aer the amplier

• Earphone – acts as the receiver by converting electrical energy to acoustic energy

• Sound Hook – delivers sound from the receiver to the ear mold

• Battery – supplies power to the amplier contained in the shell

• Internal Controls – act as the receiver by converting electrical energy to acoustic energy

• Shell – outer casing that contains all internal circuit components

As shown in gure 1, the incoming signal goes through the microphone, where it is ltered to

obtain the respective frequency response, and amplied to create a louder sound. e receiver, or

earphone, converts the signal back into an acoustical form that can be heard by the ear.

Improving Hearing Aid Performance with Bourns® Trimpot Trimming Potentiometers

05/18 • e/T1812

3312

For more information on the 3312,

including engineering les and other

resistive products from Bourns, please visit:

www.bourns.com

“Bourns” and "Trimpot" are registered trademarks of Bourns, Inc.

in the U.S. and other countries.

ADDITIONAL RESOURCES

Americas: Tel +1-951 781-5500

Email americus@bourns.com

EMEA: Tel +36 88 520 390

Email eurocus@bourns.com

Asia-Pacic: Tel +886-2 256 241 17

Email asiacus@bourns.com

WHERE THE TRIMMER IS LOCATED

AND HOW IT FUNCTIONS:

• e trimmer can be used in the

internal controls, where the

ne tuning adjustment is done by

the audiologist.

• e trimmer can be used as a

rheostat, in the volume control to

alter the current going through the

microphone and the amplier.

• In the amplier circuit, the

trimmer can help to oset the

distortion of the input signal from

the microphone. is provides for

better sound performance.

WHY MODEL 3312 TRIMMERS

ARE THE BETTER CHOICE:

During the assembly of the electronic

hardware, the microphone, amplier,

battery compartment and volume control

are soldered into place and put through a

wash process. e Bourns® Models 3312

is sealed to withstand standard wash

processes, unlike open frame trimmers.

ese 2 mm sealed trimmers are ideal for

smaller hearing aids, such as Behind-e-

Ear (BTE), In-e-Ear (ITE) and In-e-

Canal (ITC) aids.

Electrical Characteristics

Standard Resistance Range 10 Ω to 2 MΩ

Resistance Tolerance ±20 % std.

Adjustability

Voltage Divider ±0.4 %

Rheostat ±0.8 %

Resolution Essentially Innite

Adjustment Angle 255 ° nom.

Environmental Characteristics

Power Rating (50 volts max.)

70 °C 100 mW

125 °C 0 watt

Operating Temperature Range -55 °C to +125 °C

Temperature Coecient ±100 PPM/°C

Vibration 20 G TRS ±1 %; VRS ±1 %

Shock 100 G TRS ±1 %; VRS ±1 %

Rotational Life 25 cycles TRS ±3 %

MODEL 3312 SPECIFICATIONS

P1-P2

PVF2A204A1AR03

Mfr. #:

Buy PVF2A204A1AR03

Manufacturer:

Bourns

Description:

Trimmer Resistors - SMD 200Kohm 2mm Cermet

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

Payment:

T/T Paypal Visa MoneyGram Western Union

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PVF2A204A1AR03