I came upon another strange symbol. It looks like a box containing an NPN transistor symbol at one end and a diode symbol at the other. There are 2 arrows pointing from the diode symbol to the transistor symbol. The schematic I found this in says "CT324 EL817 Everlight." I searched these numbers at DigiKey.com and "CT324" is a non inverting line driver, and "EL817" is an op amp. I don't have a clue what this is. Thanks for any help.