A simple circuit to turn a 120VAC (RMS) source into a reasonably stable DC source. Consists of 3 parts:
1) TRANSFORMER
- 5:1 = converts 120VAC into 24VAC
2) FULL-WAVE RECTIFIER
- 4 diodes (a.k.a. a diode bridge) that turn the negative voltages of an AC wave into positive voltages of the same magnitude.
3) SMOOTHING CAPACITOR
- Larger capacitance gives less voltage/current variation (GREEN and ORANGE waveforms), but also increases the power-down time when the switch is opened.
4) POWER INDICATOR
- Once the switch is turned off, the LED instead shows the capacitor charge level. and the resistor "bleeds off" the capacitor charge.
