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FlyMario wrote:Damn Harry. According to Texas Instruments, my LM358 should be a replacement for the AN1358.
Did you drop in your An1358 into the circuit (hand drawn) in place of the MC1458 or where there modifications? That sync pulse is perfect.
Next and more importantly, is your real last name Dalek or is it in appreciation for the robots in Dr. Who?
Robonz wrote:Hi Harry
All of those op amps should work fine based on the specs The issue I see is most of them have a minimum working voltage of 10 volts. To do these circuits at 5 volts the right op amp must be chosen that can work on 5 volts.
The AN1358 is versatile as it runs from 3 to 30v which makes it workable for 5v. When doing any circuit the power supply must be in spec to get a desired result. While I love the TLO72 and have used them and the TLO74. They do specify that you must use at least 10v to run them in spec.
The AN1358 is good advice and any other op amp that works in the 5v region.
Cheers
Keith
Robonz wrote:Hi Fly
Its great to see you making progress. Just a couple of notes.
1) There is no decoupling capacitor across the supply of the chip/s (in your diagram). You can end up with random sync pulses without it. Each op amp should have something like a 0.1uf or 0.01uf capacitor directly across the chip.
2) The input signal should be in a coaxial cable. You can end up with random sync pulses with out it.
Also your 5V rail should have at least 47uf capacitor across it for noise suppression.
Good luck
Keith
FlyMario wrote:So here is the circuit to obtain the Sync. It matches the Club Circuit with exception of having a 200K Linear Pot to trim the trigger point and using the CA3140 OP-AMP which is a single version of the version used in the original circuit.
I am happy that I switched to the Linear Pot as it really helped me tweak the pulses to where I was happy.
]What design program do you folks use? I found this Digikey online one pretty fun but don't like when wires have to hop over other wires. It creates a headache. I would prefer the hopping(?) symbol than trying to show a break. I remember in electronic school (NAVY) in the 80's that a ball is actually proper for showing a connection but seems that is a dead standard maybe.
FlyMario wrote:Wow looks like I am being paid by Amazon.
FlyMario wrote:Do you test those big Volume control type of rotary pots by measuring the leg to the middle to find out if they are good? I tried to use one for the video signal and it seemed no good. I had to cross the video input directly into the coupling cap before I got a signal to go through the op amps.
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