Looking at your latest schematic, I'm confused about the BDW93C (TIP142 & TIP147) & BDW94C (TIP142), which one is p-n-p & which one is n-p-n? Also, a single-supply would be nice. Thanks for this great job, it is almost at a point where I can duplicate it, given my non-existent skills.Gold_xyz said:
phase_accurate said:
and i can build a coldfusion generator out of match sticks
Play fair.................. you can't tell people you have the solution to there problems and then not tell them. Come on, if you know how its done and there are several people here without your experiance that would benifit from your help, post away...............Please.
Sorry for being a bit mean but I already hinted at possible solutions before.
If you don't need a wide frequency range you can use the piezo's property of being a lossy capacitor to transform the input voltage to the desired level.
One possibility is a series tank circuit (left) and the other one is a parallel tank circuit with a tapped inductor (right). C-large is there to block DC and might not be needed in some cases (like bridge topologies). Another possibility, though very static in terms of output frequency would be the push-pull oscillator that I once posted within another thread.
Regards
Charles
If you don't need a wide frequency range you can use the piezo's property of being a lossy capacitor to transform the input voltage to the desired level.
One possibility is a series tank circuit (left) and the other one is a parallel tank circuit with a tapped inductor (right). C-large is there to block DC and might not be needed in some cases (like bridge topologies). Another possibility, though very static in terms of output frequency would be the push-pull oscillator that I once posted within another thread.
Regards
Charles
Attachments
I built the PCB for the attached schmetic of goldxyz with the power supply of +25 and -25 volts. It works fine up to 8kHz
and both transistor pairs remain cool but if you increase the frequency above 8kHz, the output waveform across the load(piezo or resistance) is no longer symmetrical. The negative portion of the output becomes longer than the positive. Also the NPN transistor extremly heats up at frequencies higher than 8kHz.
Still trying to get symmetrical output across the piezo with both cool transistors.
and both transistor pairs remain cool but if you increase the frequency above 8kHz, the output waveform across the load(piezo or resistance) is no longer symmetrical. The negative portion of the output becomes longer than the positive. Also the NPN transistor extremly heats up at frequencies higher than 8kHz.
Still trying to get symmetrical output across the piezo with both cool transistors.
