电池欠压报警电路图

电池欠压报警电路图
Circuit diagram

Radio Shack parts: Here again, you can use smaller rated resistors if you can get them--1/8 watt or less is fine. Tantalum capacitors are physically smaller, but any composition will work.
273-074 Miniature Piezo Buzzer, 12v, PC board mount
271-312 1/4 watt 5% carbon film resistors, 500 pieces (Take the plunge!)
276-1604 Package of 15 PNP small signal 2N3906-type transistors. Could use instead 276-2016 $0.59 2N3904 PNP transistors
RSU 11673505 3.3v Zener diode (not on shelf--need to order 1-800-THE-SHACK)
272-1434 1uf tantalum capacitor (see above for choice of capacitor)
RSU 11295888 2.2uF tantalum capacitor (not on shelf--need to order)
272-1024 4.7uF radial-lead electrolytic capacitor