This amplifier for hearing aid was found in a 1968 documentation using an integrated of the time. The power is from a battery, the consumption of 1.65 mA and the power of about to 1 mW.
Found in old American documentation, this circuit makes use of operational amplifiers from the 70s...
Toshiba LDO Regulators Toshiba has a wide variety of low voltage drop (LDO) linear regulators...
This circuit was published in a 1977 English magazine, but it can be easily assembled since all...