t_maggot
Joined: 09 Nov 2006
Posts: 45
Helped: 2
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 23 Mar 2009 22:01 lm7912 and lm 7812 |
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Its a simple circuit, it looks ok in general, maybe it will work, but you need also the 3 voltages +13V, -13V and +5V (+12 and -12 will also do the job)
I suggest you to do it in steps:
1. Construct the power supplies and check the voltages (+12, -12 and +5)
2. Construct the logic part (U1, U3, U4) and check if it works (U3A and U3B out)
3. Construct the operational amplifier part (U2 and U5) and check the U5 out. It must change between +12, 0 and -12 (same as U2 out)
4. Final connect Q1(npn) and Q2(pnp) and the dc motor.
**LM741 is U2 and U5, 74LS32 is the U1, 74LS04 is U4, and 74LS11 is U3. Use LM7812 for +12, LM7912 for -12 and LM7805 for +5. Good luck 
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