This is a Simple Voltage Doubler to boost 3V battery voltage to power some low-power 5V circuits. In needs a Clock input with high fan-out. You can use the 74HCT540 in parallel. Work with the Audio frequency range and see.
Mains Voltage Current LED Indicators
If you feed a Low Impedance Square wave, like output of 555, which has adequate Source-Sink Punch. to Input A, then it is quite possible you get double the voltage at B on No load.
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