Rory Starkweather
- Nov 13, 2014
- 77
- Joined
- Nov 13, 2014
- Messages
- 77
This may take a little time because I am way outside my normal area of interest.
What I want to do is test an LM7809 with a pure AC input, then with a DC input. The thing I am primarily interested in is the % ripple on the output voltage. I won't be using anything but the bare LM7809. No capacitors or anything else.
I would like to use input voltages of 18 vdc and whatever AC voltage would be comparable to that.
I'm assuming that the AC source will need to produce 18 RMS volts AC. Is that correct?
I bought two 120 VAC to 18 VDC transformer/regulators for $1.58 each. I plan to use one as is, and cut the regulator circuitry off of the other one. I'm sure this will give me more than 18VAC, but I may be able to get it down to what I need somehow.
So does anyone see any gross errors in my methodology?
BTW, I realize that I could simulate the circuit, but I would like to wait until I have real physical data and then compare that to a simulation.
This is part 1. of a project to evaluate the effects of various support circuits on the LM7809. Primary data of interest is full circuit power dissipation, Output voltage and ripple and noise on the output.
What I want to do is test an LM7809 with a pure AC input, then with a DC input. The thing I am primarily interested in is the % ripple on the output voltage. I won't be using anything but the bare LM7809. No capacitors or anything else.
I would like to use input voltages of 18 vdc and whatever AC voltage would be comparable to that.
I'm assuming that the AC source will need to produce 18 RMS volts AC. Is that correct?
I bought two 120 VAC to 18 VDC transformer/regulators for $1.58 each. I plan to use one as is, and cut the regulator circuitry off of the other one. I'm sure this will give me more than 18VAC, but I may be able to get it down to what I need somehow.
So does anyone see any gross errors in my methodology?
BTW, I realize that I could simulate the circuit, but I would like to wait until I have real physical data and then compare that to a simulation.
This is part 1. of a project to evaluate the effects of various support circuits on the LM7809. Primary data of interest is full circuit power dissipation, Output voltage and ripple and noise on the output.