Hi Everyone,
I am a newbie and am assembling a my first electronics kit since my childhood. This time it has an integrated circuit and the vague instructions warn that me to " watch the polarity" of the chip before installing it. I have attached the schematic, along with pictures of the PCB and the IC Chip.
Question: How do I determine the polarity of either the chip, the circuit schematic, or the circuit board.
Perhaps stated another way: Where is pin 1 on the chip?
Question A: What is U stand for ? As in U1 and U2 - that looks like the IC Chip holders.
Question B: What is the correct installation for U1 & U2? ----- I see the semi circular cutout depicted on the PC board as well as the components U1 & U2 therefore it appears as thought those are directional, even though these "U" components appear to be identical in either direction.
Question C: What is the correct installation for IC1 and IC2?
Looking at the Datasheet for the LM324 IC at
http://www.engineersgarage.com/electronic-components/lm324n-datasheet it appears as thought the semi-circular depression in the chip pictured would be the top of the chip, therefore pin 1 would be on the left... Just a guess on my part.
Looking at the schematic and the board I see that Pin 1 (IC Operational Amplifier 1) on U1 connects to R3 so I think I know where pin one goes... Similarly I see that on U2 the Pin 1 appears to go to R11 However on the PC Board it looks as though Pin2 goes to R11 which mystifies me.
Question D: Why are there multiple datasheets for these chips when they appear to be the same?
I tried to look up the datasheet and found a bunch listed at:
http://www.alldatasheet.com/view.jspAt the TI website I found yet a different set of parameters that may or may not equate to these datasheets.
http://www.ti.com/product/lm324Any help you could give would be greatly appreciated.
Thank you.
Jim
(JeepRadioGuy)