# Rectifier/Filter Circuit

## Chapter 5 - Discrete Semiconductor Circuits

PARTS AND MATERIALS

• Low-voltage AC power supply
• Bridge rectifier pack (Radio Shack catalog # 276-1185 or equivalent)
• Electrolytic capacitor, 1000 µF, at least 25 WVDC (Radio Shack catalog # 272-1047 or equivalent)
• Four “banana” jack style binding posts, or other terminal hardware, for connection to potentiometer circuit (Radio Shack catalog # 274-662 or equivalent)
• Metal box
• 12-volt light bulb, 25 watt
• Lamp Socket

A bridge rectifier “pack” is highly recommended over constructing a bridge rectifier circuit from individual diodes, because such “packs” are made to bolt onto a metal heat sink. A metal box is recommended over a plastic box for its ability to function as a heat sink for the rectifier. A larger capacitor value is fine to use in this experiment, so long as its working voltage is high enough. To be safe, choose a capacitor with a working voltage rating at least twice the RMS AC voltage output of the low-voltage AC power supply. High-wattage 12-volt lamps may be purchased from a recreational vehicle (RV) and boating supply store. Common sizes are 25 watts and 50 watts. This lamp will be used as a “heavy” load for the power supply. CROSS-REFERENCES Lessons In Electric Circuits, Volume 2, chapter 8: “FiltersLEARNING OBJECTIVES

• Capacitive filter function in an AC/DC power supply
• Importance of heat sinks for power semiconductors

Fullwave bridge rectifier v1 1 0 sin(0 8.485 60 0 0) rload 2 3 10k c1 2 3 1000u ic=0 d1 3 1 mod1 d2 1 2 mod1 d3 3 0 mod1 d4 0 2 mod1 .model mod1 d .tran .5m 25m .plot tran v(1,0) v(2,3) .end