I have been researching op amps recently, and I have been wondering: can they amplify DC power? I know power is the product of voltage and current, and I know they can amplify voltage and current, but is the power delivered to the output higher than what you start with at the input?
2007-07-05 00:37:29 · 3 answers · asked by Confused about life 2 in Science & Mathematics ➔ Engineering
Poster above is a bit mis-informed. Opamps in general work exceedingly well at very low frequencies, including DC. And yes, they definitely can amplify power, in fact there are power opamps available with outputs in the dozens of watts for audio amps that can drive 8 ohm speakers directly.
Many common opamps can drive 10 kohm loads to +/-15V at full bandwidth with little distortion, or can drive down to say 100 ohm loads with low distortion but at reduced bandwidth or less gain.
And of course, most opamp circuits have very high input impedance, which means they require very little power to drive. In fact, the "ideal" opamp has infinite input impedance and therefore draws zero power from the source. No real opamp is ideal, but in many cases is close enough to it that you can simplify your design by assuming is is ideal, then fine-tweak it to allow for its real characteristics. Feel free to email me if you need more info.
2007-07-05 02:12:34 · answer #1 · answered by Gary H 6 · 0⤊ 0⤋
To further clariy... Op Amps don't "manufacture" power. In otherwords, they are able to amplify a DC voltage, and (some types) provide many Watts of power to a load from a source that is providing only microWatts, but that power is derived from the OpAmp power supply, not the OpAmp itself. The OpAmp is there to amplify the voltage, and if the load is very low (resistance), channel enough current at that amplified voltage from the power supply to the load.
There is still power being consumed by the OpAmp itself (internal resitors and transistors), so it is not 100% efficient in providing power to the load.
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2007-07-05 04:22:52 · answer #2 · answered by tlbs101 7 · 0⤊ 0⤋
No, op amps do not amplify dc. Remember that power is always conserved. Power at the output is always equal to power at the input plus power drawn from the power supply.
2007-07-05 02:11:41 · answer #3 · answered by Anonymous · 0⤊ 0⤋