Hi Ged.
Yes, I did some measurements of voltage and current at the input and the output, and calculated the power input and output. The meter I was using is an ordinary digital multimeter, so the AC readings are not accurate, since the frequency was about 40 KHz. Still, these readings give some indication of what was taking place. The device was powered by a 12 volt lead acid gel cell battery of 5 ampere hour capacity.
Input voltages were measured across the resonant tank circuit composed of the L1 coil and the 0.1 uF capacitor. The output voltage was measured across the load.
# of Bulbs Input Amps Output Amps
1 1.236 0.15
2 1.086 0.26
3 0.980 0.35
4 0.905 0.40
# of Bulbs Input AC Volts Output DC Volts
1 15.98 3.23
2 14.65 5.12
3 15.70 4.12
4 15.77 3.25
# of Bulbs Input Power Output Power
1 19.75 0.485
2 15.9 1.331
3 15.39 1.442
4 14.27 1.300
As shown above, the input power requirement generally becomes less as more lamps are added to the output, yet the circuit is able to run the lamps. The lamps were miniature 7.5 volt types.
I tuned the circuit just by changing a small trimmer potentiometer used with the 555 circuit. The 555 was driving an IRF510 power MOSFET. The input tank circuit was connected to the 12 volts, and the drain of the MOSFET. The tuning is done only one time by watching for maximum brightness of the lamp or lamps. Then you can connect additional lamps and even a small DC motor.
I would like to upload pictures, but when I tried to do that it said it needed a website where it can get the pictures. I need more information on how to upload pictures from my hard disk to the forum.
Thanks.
Yes, I did some measurements of voltage and current at the input and the output, and calculated the power input and output. The meter I was using is an ordinary digital multimeter, so the AC readings are not accurate, since the frequency was about 40 KHz. Still, these readings give some indication of what was taking place. The device was powered by a 12 volt lead acid gel cell battery of 5 ampere hour capacity.
Input voltages were measured across the resonant tank circuit composed of the L1 coil and the 0.1 uF capacitor. The output voltage was measured across the load.
# of Bulbs Input Amps Output Amps
1 1.236 0.15
2 1.086 0.26
3 0.980 0.35
4 0.905 0.40
# of Bulbs Input AC Volts Output DC Volts
1 15.98 3.23
2 14.65 5.12
3 15.70 4.12
4 15.77 3.25
# of Bulbs Input Power Output Power
1 19.75 0.485
2 15.9 1.331
3 15.39 1.442
4 14.27 1.300
As shown above, the input power requirement generally becomes less as more lamps are added to the output, yet the circuit is able to run the lamps. The lamps were miniature 7.5 volt types.
I tuned the circuit just by changing a small trimmer potentiometer used with the 555 circuit. The 555 was driving an IRF510 power MOSFET. The input tank circuit was connected to the 12 volts, and the drain of the MOSFET. The tuning is done only one time by watching for maximum brightness of the lamp or lamps. Then you can connect additional lamps and even a small DC motor.
I would like to upload pictures, but when I tried to do that it said it needed a website where it can get the pictures. I need more information on how to upload pictures from my hard disk to the forum.
Thanks.
Comment