I purchased this item:
NTE7426 IC TTL Quad 2−Input High Voltage Positive NAND Gate
http://www.radioshack.com/product/index.jsp?productId=20797106
datasheet: http://nte01.nteinc.com/nte\NTEMasterxRef.nsf/$all/94258C081D8B8E1D85257BA5006B8ABA?OpenDocument
Its also sold at Fry's
I'm giving the item because I'm thinking it may have something to do with my problem, and I want to find out if someone has tried to use it before.
I'm a database guy who likes to tinker around with new things and my latest discovery area is electronics. I'm mostly motivated by modifying and repairing old video game equipment, so I'm working through a prototype of a controller for the old Intellivision console. There's some good walk-thru's to follow and they require a NAND gate.
Anyway, I've connected the thing up in the simplest way that I can and I can't seem to get any kind of output voltage from the output pins. I must be doing something wrong. Here are the simplest steps that I've gone through to try and produce a result.
1) Insert 7426 into Breadboard across the 2 halves
2) Connect a battery power supply to + and negative rails and then connect + to Vcc (pin 14) and - to Gnd (pin 7)
From here I started complicated and got more basic. I'm pretty confident that I'm reading the pinout diagram correctly, so I don't think that's a problem. The NTE7426 doesn't mark pin 1 explicitly, but the "notch" does a good job of showing that pin 1 is just below it.
Ok, so my plan here was to simply connect wires to the + rail and create two high inputs. Then my experiment continues as I move the wires from + to - (gnd). If I'm thinking about this correctly then two wires connected between + and pins 1 and 2 should be the only scenario where pin 3 produces a low output.
BTW, I'm using a battery supply that has 4 AA batteries in it. I have batteries that produce different voltages available (different degrees of dead), but I was mostly using an output voltage of about 5.2V.
So I connect pins 1 and 2 to the + rail and pin 3 doesn't really do anything. I'm probing around measuring voltage supplied on pin 1 &2 (to ground), and I find the 5.2v on both. So the volts should be low on 3 - problem is that the volts on pin 3 when measured to ground are always low. No matter what combo of + or - connections that I make with my two wires on pins 1 and pins 2.
Its interesting that the millivolts detected on pin 3 do change, but it goes between something like 70mV down to 2mV
The other disconnected input pins show a voltage of 1.6v and the output pins have about 70mV
Just trying to think through what could be wrong, and I've come up with stuff like:
1) Not enough amps
2) Bad IC (although I've tried 2)
3) Some kind of noise
I've tried connecting with resistors instead of wire to pins 1 & 2 but that doesn't change anything. Next I was going to connect VCC with a resistor, but I don't understand why I'd need to. I've also contemplated wiring the unused inputs and outputs.
Anyone spot any common mistakes in my description here?
NTE7426 IC TTL Quad 2−Input High Voltage Positive NAND Gate
http://www.radioshack.com/product/index.jsp?productId=20797106
datasheet: http://nte01.nteinc.com/nte\NTEMasterxRef.nsf/$all/94258C081D8B8E1D85257BA5006B8ABA?OpenDocument
Its also sold at Fry's
I'm giving the item because I'm thinking it may have something to do with my problem, and I want to find out if someone has tried to use it before.
I'm a database guy who likes to tinker around with new things and my latest discovery area is electronics. I'm mostly motivated by modifying and repairing old video game equipment, so I'm working through a prototype of a controller for the old Intellivision console. There's some good walk-thru's to follow and they require a NAND gate.
Anyway, I've connected the thing up in the simplest way that I can and I can't seem to get any kind of output voltage from the output pins. I must be doing something wrong. Here are the simplest steps that I've gone through to try and produce a result.
1) Insert 7426 into Breadboard across the 2 halves
2) Connect a battery power supply to + and negative rails and then connect + to Vcc (pin 14) and - to Gnd (pin 7)
From here I started complicated and got more basic. I'm pretty confident that I'm reading the pinout diagram correctly, so I don't think that's a problem. The NTE7426 doesn't mark pin 1 explicitly, but the "notch" does a good job of showing that pin 1 is just below it.
Ok, so my plan here was to simply connect wires to the + rail and create two high inputs. Then my experiment continues as I move the wires from + to - (gnd). If I'm thinking about this correctly then two wires connected between + and pins 1 and 2 should be the only scenario where pin 3 produces a low output.
BTW, I'm using a battery supply that has 4 AA batteries in it. I have batteries that produce different voltages available (different degrees of dead), but I was mostly using an output voltage of about 5.2V.
So I connect pins 1 and 2 to the + rail and pin 3 doesn't really do anything. I'm probing around measuring voltage supplied on pin 1 &2 (to ground), and I find the 5.2v on both. So the volts should be low on 3 - problem is that the volts on pin 3 when measured to ground are always low. No matter what combo of + or - connections that I make with my two wires on pins 1 and pins 2.
Its interesting that the millivolts detected on pin 3 do change, but it goes between something like 70mV down to 2mV
The other disconnected input pins show a voltage of 1.6v and the output pins have about 70mV
Just trying to think through what could be wrong, and I've come up with stuff like:
1) Not enough amps
2) Bad IC (although I've tried 2)
3) Some kind of noise
I've tried connecting with resistors instead of wire to pins 1 & 2 but that doesn't change anything. Next I was going to connect VCC with a resistor, but I don't understand why I'd need to. I've also contemplated wiring the unused inputs and outputs.
Anyone spot any common mistakes in my description here?