VEBill
Military
- Apr 25, 2002
- 7,090
I think I already know the answer (because it seems to be trivial), but I really want to make sure I'm not missing anything.
I'm installing a system which is rated for a supply voltage range of 9 to 30 volts DC. The available power supply is a nominal "28 volts", but the power supply specification actually allows the supply to wander up as high as above 30.5 volts. So there's an issue since 30.5 > 30.0.
I'm considering using a simple Zener diode in series with the + supply line to knock off about 6 volts. This should drop the voltage down into the sweet spot (~22 volts) and avoid the over-voltage issue.
The current is fairly low (~25mA) so the power dissipation is not a significant road block.
I've seen this simple technique used before, but it was always presented as a 'hack' (to use the modern word).
So, the question: Is there any reaon not to use a simple series Zener diode to drop a few volts? And side-effects or details that I need to watch out for?
Thanks.
I'm installing a system which is rated for a supply voltage range of 9 to 30 volts DC. The available power supply is a nominal "28 volts", but the power supply specification actually allows the supply to wander up as high as above 30.5 volts. So there's an issue since 30.5 > 30.0.
I'm considering using a simple Zener diode in series with the + supply line to knock off about 6 volts. This should drop the voltage down into the sweet spot (~22 volts) and avoid the over-voltage issue.
The current is fairly low (~25mA) so the power dissipation is not a significant road block.
I've seen this simple technique used before, but it was always presented as a 'hack' (to use the modern word).
So, the question: Is there any reaon not to use a simple series Zener diode to drop a few volts? And side-effects or details that I need to watch out for?
Thanks.