Switching amplifier (CB9001E)

We found this circuit in an old American documentation. The circuit applies to modern equivalent components. The font must be symmetrical.

Voltage Controlled Gain Amplifier (CB4898E)
This circuit provides a linear attenuation of a signal up to 100 dB. The circuit operates with...
Linearizer for RTD sensor (CB9481E)
This circuit was found in Linear Technology documentation from the 90's. The circuit uses...
LM324 Electret Microphone Amplifier (CB4838E)
The gain of this amplifier is given by the 120k resistor, which can be changed depending on the...