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Hi,
negative voltag circuit seems to be correct now and should give -6.0V ... -6.1V output.
Positive side bjt is still wrong. Replace it with an NPN and exchange emitter with collector.
R2, D7 is mysterious....
Klaus
How come it is just -6v while the source is 9v??
No, both circuit parts have errors. Q6 has collector and emitter flipped which reduces current gain B to about unity. Respectively the V- output has high output impedance, voltage drops with only small load.I confirm that the set up in the attached screen shot is working with no problem.
Hi,
* 9V battery --> bjt + zener combination --> fixed +6V output
* 9V battery --> 7660 circuit --> -9V --> bjt + zener combination --> fixed -6V output
This is what the circuit does. But you should have known this before.. did you use a voltmeter?
Klaus
The circuit absolutely will not work with a PNP transistor for Q3. Q3 MUST be an NPN for it to work properly.
Also, the emitter and collector of Q6 are backwards.
- - - Updated - - -
Why not do it correctly like this:
No, both circuit parts have errors. Q6 has collector and emitter flipped which reduces current gain B to about unity. Respectively the V- output has high output impedance, voltage drops with only small load.
Q3 has forward biased collector-base junction in series with zener diode, causing high input current above 7.5V battery voltage.
Any simulator of your choice will reveal both circuit flaws if you don't believe it.
True, indeed. The most likely explanation is that the posted schematics are not reflecting the real hardware. Less likely, that the circuit is not working according to state of the art, but nevertheless serving a purpose. In the latter case, we don't have enough information to judge if the circuit shows useful operation under the given conditions, neither load current nor load voltage range have been reported yet.yet there is something not making sense in here.
Ok 7.3V is a ranfdom voltage. We don´t know whaere you connected the DVM.at the first glance thought you were talking about the charge pump, anyway the voltmeter reads as 7.3v