I spent ages – as usual for me! – arsing about and getting nowhere with this circuit (and my crappy Hantek DSO 5102P scope and it’s usual lockup and odd behaviour type hassle, hopefully improved after a firmware update!) from page 109 of GC Loveday’s Electronic Testing book – should have been straight forward right – as easy as a circuit gets?!:
There is no Y component from this circuit as pin 1 out is grounded by the pull up resistor so has no amplitude no? I’m wondering if the +/- invert signs are error switched – though the output pin 1 is fixed the same as the inverting pin 2, with the input at non-inverting pin 3 should still work eh?But, I only got a flat line in XY mode at a 20Hz ramp so don’t know why this doesn’t work – even at 10Hz or 1kHz sine/ramp/triangle…nothing?
Do you have to have the sig gen gain cranked up more…as I found I was doing below for the working versions??
I finally made some progress with the simplest way possible to view the op amp’s output, from this guy, by using the inverting input instead with the non inverting input at ground:
This shows NO components required – just a 1-2Vpp sine wave (2kHz worked best for me) in and out (pins 2-; 1 out; 3+ to ground of a +/- 15.7V supply) to give the clearest view of the slope at my scope’s settings).
This gave me the same as him at least – digital scopes are crap in XY mode display, at best – and after trying different wave forms at different cycles/sec I found 2kHz best:
This output is from the M5219P tone amp from the Technics V1X – total symmetry as you’d expect.
This method can be used to test an op amp quickly on a bread board without building a circuit board – if you lost your tester you already built..?
LM358s at 20Hz looks like:
After changing Vcc to pin 7 and output to pin 6, the 741 op amp at 20Hz looks like: