davelectronic
- Dec 13, 2010
- 1,087
- Joined
- Dec 13, 2010
- Messages
- 1,087
I have a problem.
Any ideas as to why would be appreciated.
Any way i have built this circuit twice now, first time i thought it was my error.
The circuit consisted of two 78S12CV 2amp voltage regulators, whats happened i belive is they wont share the input supply.
I have built the same circuit with each regulator having it own rectifier and filter capacitor, so the pair did not parallel until the final isolation diodes, this circuit works fine, line and load are the same between regulators.
I set out to build a second circuit, but this time i thought the regulators would share the same source, so my first attempt burnt out one of the regulators, the second attempt did the same.
Yes i know some say there not meant to share current very well, but my first circuit works a treat, this time round i wanted to use one rectifier one filter capacitor, i have left my ok working circuit that has all separate input, and a diagram schematic of the one ive been trying, the bottom line is why wont they share the same input ? i could use diodes on the input, but this will drop the input, ground or common has two diodes to increase the voltage to 13.20 volts, as in the working first circuits it works fine, so any one have any idea why they wont share the same rectified filtered input, mad, lost a fare few components today. Dave.
This is the working ok circuit.
I got this off the REUK site, and if followed wont work if the inputs are shared.
http://www.reuk.co.uk/High-Current-Voltage-Regulation.htm
This link is the origin of the schematic, any ideas as to why they wont share the input, i would be grateful to know. Dave
Any ideas as to why would be appreciated.
Any way i have built this circuit twice now, first time i thought it was my error.
The circuit consisted of two 78S12CV 2amp voltage regulators, whats happened i belive is they wont share the input supply.
I have built the same circuit with each regulator having it own rectifier and filter capacitor, so the pair did not parallel until the final isolation diodes, this circuit works fine, line and load are the same between regulators.
I set out to build a second circuit, but this time i thought the regulators would share the same source, so my first attempt burnt out one of the regulators, the second attempt did the same.
Yes i know some say there not meant to share current very well, but my first circuit works a treat, this time round i wanted to use one rectifier one filter capacitor, i have left my ok working circuit that has all separate input, and a diagram schematic of the one ive been trying, the bottom line is why wont they share the same input ? i could use diodes on the input, but this will drop the input, ground or common has two diodes to increase the voltage to 13.20 volts, as in the working first circuits it works fine, so any one have any idea why they wont share the same rectified filtered input, mad, lost a fare few components today. Dave.
This is the working ok circuit.
I got this off the REUK site, and if followed wont work if the inputs are shared.
http://www.reuk.co.uk/High-Current-Voltage-Regulation.htm
This link is the origin of the schematic, any ideas as to why they wont share the input, i would be grateful to know. Dave