Are all your resistor values the exact same as in my simulation in post #19?I noticed that in your circuit, I had to place 5 diodes in series in order to bring the min voltage to -1v (at full range).
YEs, apart from the collector one which is 1k (shared with the positive input circuit)Are all your resistor values the exact same as in my simulation in post #19?
Of course it matters.YEs, apart from the collector one which is 1k (shared with the positive input circuit)
If that matters then I can alter the input circuit.
I would really like the inverter circuit not to require a negative VCC to operate.
This is very interesting too!Simple method to lift a negative voltage into the positive range 0-5V. Potentiometer selects a midway position between your incoming signal and supply +6.6 V.
View attachment 174112
Most simulations and circuit suggestions seems to ignore the high source impedance (1 MOhm) of AGC voltage. The JFET inverter circuit is the circuit idea that has potentially a sufficiebt input impedance, except for the 1 M pot which should be replaced by a voltage divider with higher impedance.
Do I understand right, that an auxiliary negative power supply like -5V in post #7 can be provided?
I tried replacing that 1k collector resistor at the second stage of your circuit to 10k.Saying so, I find a tendency to oscillate in curtschow circuit. At low input voltages, the output voltage is not stable like the input is, but it tends to go up and down a few milivolts, which causes the display to deviate a bit up and down.
I still haven't tried to change the collector resistor to 10k (I will do this later) but can I do something to fix this?
The circuit is very simple with no feedback, so I doubt that it is oscillating.I just noticed though (#19) a tendency to "oscillate".
Well, that will reduce the output voltage span along with the deviation.am thinking of replacing the collector resistor at the second stage of your circuit to 100 ohms or so, so see the difference.
Yes, I tested it and it is better to have the resistor to 10k (with 2 diodes like you said).The circuit is very simple with no feedback, so I doubt that it is oscillating.
You are likely just seeing some input variation which is amplified by the circuit.
What is the frequency of this deviation?
Well, that will reduce the output voltage span along with the deviation.
So I assume you don't have an oscilloscope to look at the signal(?)If I had an analogue multimeter I could tell you the voltage value ends, but my digital multimeter cannot catch up with this rate
I found the source of instability. The gain of the PNP needed to be set at minimum by setting the emitter of the PNP with a 165K. It's collector is tied to ground with 10k.So I assume you don't have an oscilloscope to look at the signal(?)
What do you read with the meter set to measure AC?
That means the output load must be very high to get any output voltage.The gain of the PNP needed to be set at minimum by setting the emitter of the PNP with a 165K.
Which is good or bad? or neither?That means the output load must be very high to get any output voltage.
Depends upon the load resistance you are driving.Which is good or bad? or neither?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?