Input circuit needed for PC Oscilloscope! - Electronic Circuits Projects Diagrams Free

princejim · 22nd April 2007, 09:35 AM

I have bought a PIC pc Oscilloscope but it will only except a 5v input. I have been trying to design an input circuit to reduce voltage that I am looking at from upto 20v amplitude to the 5volts needed by the scope. I am using crocodile clips to simulate the circuit, tried a simple devider and also using op-amp but not able to get any of my circuits working, anyone out there have a decent circuit I can use, please.

ericgibbs · 22nd April 2007, 10:17 AM

hi,
Have you tried a resistor divider as shown in the diagram, if so, what value did the PIC scope show?

Sceadwian · 23rd April 2007, 07:45 AM

Zener diodes begin conduction in the 'reverse' direction when their 'zener voltage' is reached, which should be placed in front of this circuit at the absolute maximum voltage level allowed by the USB scope, to prevent transients from the external circuit from killing it. It's the bare minimum protection I'd put on it, unless you can be absolutly sure the circuit will never get a transient.

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22nd April 2007, 09:35 AM	#1
princejim	Input circuit needed for PC Oscilloscope! I have bought a PIC pc Oscilloscope but it will only except a 5v input. I have been trying to design an input circuit to reduce voltage that I am looking at from upto 20v amplitude to the 5volts needed by the scope. I am using crocodile clips to simulate the circuit, tried a simple devider and also using op-amp but not able to get any of my circuits working, anyone out there have a decent circuit I can use, please.

22nd April 2007, 10:17 AM	#2
ericgibbs	hi, Have you tried a resistor divider as shown in the diagram, if so, what value did the PIC scope show? __________________ Eric " Good enough is Perfect " I will NOT answer PM's requesting technical help, please use the Forum PIC tutorials: Nigel's www.winpicprog.co.uk/ Bill's: www.blueroomelectronics.com/ Last edited by ericgibbs; 7th July 2008 at 12:19 PM.

23rd April 2007, 07:45 AM	#3
Sceadwian	Zener diodes begin conduction in the 'reverse' direction when their 'zener voltage' is reached, which should be placed in front of this circuit at the absolute maximum voltage level allowed by the USB scope, to prevent transients from the external circuit from killing it. It's the bare minimum protection I'd put on it, unless you can be absolutly sure the circuit will never get a transient. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."