I made a circuit to demonstrate the work of a 555 and a constant current regulator and wanted to add triangle wave input. I've done that by integrating the output of a 555 timer, and at the node 'tri' I do get the desired triangle wave of ~ +-8V. Since I want the the voltage positive at all times (for the triangle to go from 0 to 8V), I added 8 Volts DC to the triangle signal. The node 'Vin' should be \[ Vin=\frac{V_{tri}}{2}+\frac{8V}{2} \]. However, what I get is a cut off triangle wave at node 'Vin', at about 6V, even though the output of the 555 at the point 'tri' is correct. I can't seem to figure out what is the cause of this, I could use some help.
And the voltages at nodes tri and Vin, as well as the collector current (not relevant, that part works):
*Rthres and Q2 are there to limit the current through the diode if need be, but since Rthres=0 they don't play a part in this case. Opamps are 741s with +-15V supply.
And the voltages at nodes tri and Vin, as well as the collector current (not relevant, that part works):
*Rthres and Q2 are there to limit the current through the diode if need be, but since Rthres=0 they don't play a part in this case. Opamps are 741s with +-15V supply.