Wattmeter (T1351E)

This circuit is from a February 1949 Radio Electronics magazine. The circuit uses 3 tubes and includes the power supply.

Temperature controlled oscillator (CB7528E)
The thermistor used in this circuit must have a resistance at room temperature between 10 and...
Low Impedance Preamplifier (NE0020)
This circuit is intend to be used with low impedance transducers like magnetic pick-ups for...
aa CMOS Amplifier with Gains +1 and -1 (CB4621E)
The interesting circuit shown in the figure can have its gain digitally controlled and have two...