1. Chris Farrar cjf154@psu.edu Hex Inverter – 7404, 74LS04, and 7405
Pins: VCC, Ground, Input, Output
7404 In
VCC
Propagation Delay: 12ns - Typ
Out In
Price: 59 cents In
Out
Out In
74LS04 In
Out
Out In
Propagation Delay: 9ns - Typ
GND
Out
Price: 29 cents
7405
Propagation Delay: 40ns - Typ
Price: 29 cents

2. 7404 & 74LS04 – Hex Inverters 7404 74LS04 VCC 5V VIH 2V - Min 2V – Min
VIL
0.8V - Max
IOH
-0.4mA - Max
IOL
16mA - Max
8mA - Max
VOH
3.4 V
3.4V
VOL
0.2V
0.25V
IIH
40uA - Max
20uA – Max
IIL
-1.6uA - Max

3. Calculating R
This inverter with an open collector output can be thought of as a switch. When ground is connected to the input the switch is considered closed, when 5 v is connected to the input the switch is considered open.
Since current only goes into this device, in order to figure out R, you must first find how much current you need. The device alone can only handle 16 mA. So for an example, the minimum resistance that R can be for this device is 5V/16mA or ohms.