TEST EQUIPMENT
DC to AC converter
The EP-1 AC-DC unit is supplied with a conventional oscilloscope probe. With the AudioSuite software it allows you to measure and log AC or DC voltages over short or long periods using the sound card in a PC.
The EP-
2 cc Coupler set for Hearing Aid Measurements
For hearing aid measurements according to ANSI and IEC standards. The coupler set has adapters for In-The-Ear, Behind-The-Ear and Body-Worn hearing aids. The coupler set is supplied with a half-inch microphone and a long life (2 year) battery power supply.
Probe microphone
The probe microphone has a soft silicon probe tube for measuring in-situ hearing aid response (insertion gain). With the AudioSuite software it can also be used for measurements in inaccessible spaces such as loudspeaker cabinets, conduits, etc.
The Sound Card Probe consists of a chopper circuit that converts a DC voltage into an 800 Hz (approximately) square wave that can be read by a 16 bit sound card in a computer. It is intended for use with the AudioSuite Spectrum Analyzer and Oscilloscope. The spectrum analyzer can be used to log DC voltage changes over time periods up to 6 weeks. The oscilloscope voltmeter is calibrated with any known DC voltage.
The circuit is very stable and accuracy is dependent on the calibration source.
Switch OFF to measure AC
Switch ON to measure DC
Touch probe to switch to test probe batteries (3 volts)
Discard batteries at 2 volts
Avoid overloading the sound card
Normally the max. input to a sound card is 1,6v to 4v (depending on card)
For DC measurements the AC output is an asymmetrical square wave.
The narrow trace represents negative voltage, the broad trace is positive.
Specifications: Input impedance = 20000 Ohms Output voltage = half input voltage (AC or DC) Max. Input = 10v (x1 probe setting)
NB: Do not exceed Sound Card Maximum (3.2v for 1,6v input sound card)
Power supply: 2 size AA Alkaline cells
Battery Life = approx. 5 months continuous use (3600 hours)
Switching noise = 7mV AC (for DC measurements only)
Phase response (AC) = 0 deg.
The circuit is very stable and accuracy is dependent on the calibration source.
Switch OFF to measure AC
Switch ON to measure DC
Touch probe to switch to test probe batteries (3 volts)
Discard batteries at 2 volts
Avoid overloading the sound card
Normally the max. input to a sound card is 1,6v to 4v (depending on card)
For DC measurements the AC output is an asymmetrical square wave.
The narrow trace represents negative voltage, the broad trace is positive.
Specifications: Input impedance = 20000 Ohms Output voltage = half input voltage (AC or DC) Max. Input = 10v (x1 probe setting)
NB: Do not exceed Sound Card Maximum (3.2v for 1,6v input sound card)
Power supply: 2 size AA Alkaline cells
Battery Life = approx. 5 months continuous use (3600 hours)
Switching noise = 7mV AC (for DC measurements only)
Phase response (AC) = 0 deg.