This hearing aid or stethoscope headset amplifier was found in a 1980s documentation. The transistors can be the BFY22, BC148 and many other high-gain silicon transistors. The handset is a high impedance type.
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This hearing aid or stethoscope headset amplifier was found in a 1980s documentation. The transistors can be the BFY22, BC148 and many other high-gain silicon transistors. The handset is a high impedance type.
