[sdiy] My 4069 attempt not working

[René Schmitz]

Hi Nicolai,

Nicolai Czempin wrote:
> Can someone help please? "Just" a walkthrough as to what I should see on 
> the scope at certain key points would be very helpful.

It would be easier for us to tell whats wrong, if you told us what you 
observe at the integrator output, the first and second gate of the 
schmitt trigger. (There is supposed to be a sawtooth sitting arround 
Vcc/2 at the integrator output, and discharging pulses (going high for 
about 1us) at the schmitt trigger output, and the inverted version of 
those pulses at the junction of the two schmitt trigger gates. But thats 
not going to help you, since the pulses wont be there, if there is no 
saw, and vice versa.)

Does the 4069 have V+ connected to pin 14? Do you read 0 ohms between 
pin 7 and  GND?

You can confirm that the expo current source (err sink, whatever)
is working by disconnecting it from the integrator, and running the 
collector of T2 to V+ through a DVM (current reading) and a 1k in 
series. (The latter to protect the DVM.)
Its ok, if reading somewhere between a couple uA to some mA.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159