Hello All,
I think I am really burning out parts but I can’t be sure. I have had some luck with simple transistor circuits but now that I purchased some IC chips they don’t seem to be behaving as I expected. Then after I play with them for a few minutes they don’t even seem to behave the same as when I first started working with. It is at this point I throw them in the questionable part bin and grab another of the same model. After a few iterations of this I thought I’d better seek help.
I bought the chips below
74HTC04 Hex Inverter
74HC138B1R 3 To 8 Decoder (Inverted)
74HC238N 3 to 8 Decoder (Non-Inverted)
From their data sheet I believe these are all 5 volt chips. On all the chips I am connecting the ground to GND and VCC Pins.
On the decoders I am connecting 5 Volt negative to one of the three input pins and that special input pin that enables the outputs on the entire chip. On the 0-3 output pins I have connected LEDs and the appropriate resistors but they never light. I eventually applying negative voltage between the chips output and the led resistor to get the led to come on and my bench power supply shuts down. (It’s a homemade power supply I made from a PC power supply. It shuts down when there is a short)
On the Hex Inverter I connected the same diode and resistor combo to one of the inverter outputs. Now the LED lights but when I supply 5 volt negative to that inverters input the LED stays lit. Sometimed it dims slightly but never goes out as I thought an inverter would. After a few minute of fiddling I can eventually get the LED to go out but it never comes back on. At this point I think I have killed the chip.
No smoke or funny smells but I believe I have killed 5 chips of each type so far. If I were to ask specific questions they would be…
Is 5 volt too much for these chips?
Is applying reverse voltage of 5 volt enough to kill chips of this type? Meaning mistakenly applying negative 5 to the output side of the chip.
How bad is static to modern chips? It’s still warm and humid here and it’s not like I am dragging my feet on a carpet or anything. But I am not wearing a static wrist band either.
Any other ideas what I could be doing wrong?
Any tips for working with these types of chips?
Hope you guys can help?
Dave
I think I am really burning out parts but I can’t be sure. I have had some luck with simple transistor circuits but now that I purchased some IC chips they don’t seem to be behaving as I expected. Then after I play with them for a few minutes they don’t even seem to behave the same as when I first started working with. It is at this point I throw them in the questionable part bin and grab another of the same model. After a few iterations of this I thought I’d better seek help.
I bought the chips below
74HTC04 Hex Inverter
74HC138B1R 3 To 8 Decoder (Inverted)
74HC238N 3 to 8 Decoder (Non-Inverted)
From their data sheet I believe these are all 5 volt chips. On all the chips I am connecting the ground to GND and VCC Pins.
On the decoders I am connecting 5 Volt negative to one of the three input pins and that special input pin that enables the outputs on the entire chip. On the 0-3 output pins I have connected LEDs and the appropriate resistors but they never light. I eventually applying negative voltage between the chips output and the led resistor to get the led to come on and my bench power supply shuts down. (It’s a homemade power supply I made from a PC power supply. It shuts down when there is a short)
On the Hex Inverter I connected the same diode and resistor combo to one of the inverter outputs. Now the LED lights but when I supply 5 volt negative to that inverters input the LED stays lit. Sometimed it dims slightly but never goes out as I thought an inverter would. After a few minute of fiddling I can eventually get the LED to go out but it never comes back on. At this point I think I have killed the chip.
No smoke or funny smells but I believe I have killed 5 chips of each type so far. If I were to ask specific questions they would be…
Is 5 volt too much for these chips?
Is applying reverse voltage of 5 volt enough to kill chips of this type? Meaning mistakenly applying negative 5 to the output side of the chip.
How bad is static to modern chips? It’s still warm and humid here and it’s not like I am dragging my feet on a carpet or anything. But I am not wearing a static wrist band either.
Any other ideas what I could be doing wrong?
Any tips for working with these types of chips?
Hope you guys can help?
Dave