Mini Megaphone (CB8952E)

Found in Popular Electronics' 90s, this small megaphone is based on LM386. The circuit uses a high impedance microphone.

Window Comparator I (CB24973E)
Using the CA3140 in the figure we have a comparator that goes low in the window voltage space. The...
RTD amplifier (CB12808E)
This circuit is found in a 2011 technical publication from Texas Instruments. It is an amplifier for...
Overload indicator (CB22131E)
In this circuit, the LED lights up when the current is such that multiplied by the resistor value...