Photodiode selective preamplifier (CB7816E)

Found in American documentation, this circuit for modulated infrared signals can be tuned to a certain frequency. The photodiode can be of any type.

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Fire alarm (CB21361E)
Found in English documentation, this circuit uses a thermistor as a sensor. The trigger point is...
Inverter Amplifier MC1558 (CB4019E)
The circuit is from the 1990 Motorola Linear Databook. Equivalent operations can be used and what...
Rain Alarm (CB6267E)
We find this circuit in an old documentation, but it can be made using modern transistors. The circuit...