Where to get a simple datasheet? for LMF90

Started by RobertMacy in sci.electronics.design8 years ago 12 replies

This is a simple switched capacitor filter made by National. Would somebody send me a copy, or at least provide a URL that HAS it!!! and not ...

This is a simple switched capacitor filter made by National. Would somebody send me a copy, or at least provide a URL that HAS it!!! and not datasheet or alldata crap! If AppNote available that too please. I just went through the most frustrating 45 minutes trying to get a simple !@#$#@!#$ data sheet! Google search shows 8,000+ pages of either alldata, or datasheet, ok so tried goi...


Tiny membrane converts radio waves to light

Started by Jan Panteltje in sci.electronics.design8 years ago 5 replies

Tiny membrane converts radio waves to light: ...

Tiny membrane converts radio waves to light: http://physicsworld.com/cws/article/news/2014/mar/05/tiny-membrane-converts-radio-waves-to-ligh t They bounce a laser beam of a DC biased capacitor that vibrates at its mechanical resonance when hit by radio waves. The new device has a room-temperature sensitivity of 100 pV Hz\u20131/2 for radio waves at 1 MHz. That sensitivity could be improved


Weight of a 1210 SMT capacitor?

Started by Jeff Liebermann in sci.electronics.design8 years ago 21 replies

Google search has finally failed me. I can't find the weight of a 1210 SMT capacitor so that I can guestimate its final temperature from the...

Google search has finally failed me. I can't find the weight of a 1210 SMT capacitor so that I can guestimate its final temperature from the dissipation and the specific heat. All I can find is either zero grams or weights that include the packaging material. Specifically, I need the approximate weight of a AVX 1210 SQ CB series cap: Yes,


Allen Brtadley pilot light question

Started by Don Lancaster in sci.electronics.design8 years ago 3 replies

Some allen bradley pilot lights or lighted pushbuttons accept a 110 vac input to drive a 6 volt 1966 incandescent pilot light. One example is...

Some allen bradley pilot lights or lighted pushbuttons accept a 110 vac input to drive a 6 volt 1966 incandescent pilot light. One example is their 800T-PB16. The stepdown circuit appears to be something of a mystery and not a transformer as infinite resistance is measured on the 110 vac lamp terminals. And using a capacitor alone for a bulb drop is really dumb because of possible s...


Synchronous post-rectification

Started by Piotr Wyderski in sci.electronics.design8 years ago 3 replies

Hello, my master power supply provides me with synchronously rectified, but not filtered (!) AC current. For the used 12V toroidal...

Hello, my master power supply provides me with synchronously rectified, but not filtered (!) AC current. For the used 12V toroidal transformer the output waveform is thus 17V*abs(sin(50Hz)), up to 40A. I want to use this supply to power a bank of 10 SEPIC switchers. Issume 20A load in the worst case. It means I must post-rectify the input current in order to feed a big filter capacitor. Th...


Vaccum capacitor failure oddness.

Started by Maynard A. Philbrook Jr. in sci.electronics.design8 years ago 4 replies

While analyzing a problem with a small (150Kwatt oscillator) circuit, we discovered a faulty 200 pf 30VK vacuum cap. This was found via...

While analyzing a problem with a small (150Kwatt oscillator) circuit, we discovered a faulty 200 pf 30VK vacuum cap. This was found via a series of HI-POT testing, starting with the filament transformer (250 amps) which acts as the tube heater and tap for the cathode (-) voltage ( the + is grounded in this circuit) First intentions were to determine if the transformer had a leak...


Simulating Power Bandwidth

Started by Jim Thompson in sci.electronics.design7 years ago 19 replies

I'm trying to do a simulation to show power bandwidth for a (high power) OpAmp versus compensation capacitor. In the lab I would simply crank...

I'm trying to do a simulation to show power bandwidth for a (high power) OpAmp versus compensation capacitor. In the lab I would simply crank up the signal generator amplitude until the output became triangular rather than sinusoidal. Collect all the data for peak amplitudes versus frequency and then plot. Any ideas how I might do that automatically in a simulator, generating a family...


Capacitor + inductor filter - please check

Started by Dave Rove in sci.electronics.design7 years ago 15 replies

I'm learning how you use complex numbers to model reactance, and trying out a few examples. So if I string a capacitor between the input and...

I'm learning how you use complex numbers to model reactance, and trying out a few examples. So if I string a capacitor between the input and output, and put an inductor between the output and the ground like this: Vin ---||--------Vout | ) ) ) | ------------------ Then the gain G = Vout/Vin = Xl/(Xl+Xc) = jwL/...


can a 3 Ufd ac start capacitor be replaced with a 3 Ufd 600 volt dc capacitor

Started by BEN in sci.electronics.design7 years ago 25 replies

I have a small fan motor that has uses a 3 ufd start capacitor This capacitor checks bad. It is also very old (60 years) and in a fan. Can I...

I have a small fan motor that has uses a 3 ufd start capacitor This capacitor checks bad. It is also very old (60 years) and in a fan. Can I substitute a 3 ufd capacitor rated at 600 vdc to check the fan motor. I checked the voltage to the fan and it is 115 volts ac with the switch set at high speed. Your advice would be very much appreciated. Regards. Ben --


Is mcu pwm a decent way to control a power led current?

Started by Anonymous in sci.electronics.design7 years ago 75 replies

I have a project whereby I am energizing a single 10W LED at 12 volts. I am controlling the current with a logic mosfet controlled by pwm from...

I have a project whereby I am energizing a single 10W LED at 12 volts. I am controlling the current with a logic mosfet controlled by pwm from the mcu. the questions are: Is it useful to put a capacitor in parallel with the led? The idea is obviously to get smoothing. Another issue is to monitor current by the mcu. This is not absolutely necessary, but wonder if there is a trick to get ...


Large Noise from Bridge Rectifier; Conducted Emission Measurement

Started by Klaus Kragelund in sci.electronics.design7 years ago 21 replies

Hi I am working on a high power frequency inverter (> 1kW) and have a "funny" looking emission graph The converter is the typical inverter...

Hi I am working on a high power frequency inverter (> 1kW) and have a "funny" looking emission graph The converter is the typical inverter type, EMC filter-> 3 Phase Rectifier-> DC Inductor-> DC Link capacitor-> 6 switch Inverter-> Motor Like this: www.electronicsdesign.dk/tmp/Inverter.jpeg We stripped down the circuits and isolated the noise to the EMC filter and bridge rectifier. T


Interesting power supply

Started by Anonymous in sci.electronics.design7 years ago 18 replies

Seems to be just a full-bridge rectifier and capacitor voltage divider. Just wondering how well it...

Seems to be just a full-bridge rectifier and capacitor voltage divider. Just wondering how well it works: http://www.ebay.com/itm/90pcs-220UF-63V-Low-impedance-power-amplifier-AC-DC-POWER-SUPPLY-BOARD-D IY-KIT-/370877884267?pt=US_Amplifier_Parts_Components&hash=item565a0b676b How much current can you get out of it? It says 25A rectifier, but not sure about output current.


capcitors for energy reserve

Started by Richard in sci.electronics.design7 years ago 95 replies

I have a circuit that draws 30mA except that there is a 150ms long draw at 120mA. This occurs every 2s. I I am limited to 40mA current draw. ...

I have a circuit that draws 30mA except that there is a 150ms long draw at 120mA. This occurs every 2s. I I am limited to 40mA current draw. I would like to provide reserve energy from a large capacitor. I have built a circuit that limits the input current to 40mA. This runs the circuit and charges the cap. I have run caps up to 3300uF, the cap voltage drops to far and in too short a tim...


Review: Elenco CS-440 capacitor box

Started by John Larkin in sci.electronics.design5 years ago 18 replies

I'm tuning a bunch of control loops on breadboards so I figured a capacitor box would be handy. Amazon had the Elenco so I got one. It was...

I'm tuning a bunch of control loops on breadboards so I figured a capacitor box would be handy. Amazon had the Elenco so I got one. It was intermittent so I opened it up to see why. Amazing garbage. https://dl.dropboxusercontent.com/u/53724080/Gear/Elenco/Elenco_CS-440_1.JPG https://dl.dropboxusercontent.com/u/53724080/Gear/Elenco/Elenco_CS-440_2.JPG https://dl.dropboxusercontent.co...


Almost All Digital Electronics L/C Meter IIB

Started by Robert Baer in sci.electronics.design7 years ago 11 replies

On semi-rare occasions,when i am measuring capacitors,the meter will say "Not a capacitor" and re-zeroing does not help. What is going...

On semi-rare occasions,when i am measuring capacitors,the meter will say "Not a capacitor" and re-zeroing does not help. What is going on? Dew it need fixing?


Doubt in working RC differentiator

Started by Abhijith M in sci.electronics.design7 years ago 6 replies

Hey, I am a beginner in electronics , Will the RC differentiator... differentiate like in mathematics Is THIS possible Vi = sin2wt , Vo...

Hey, I am a beginner in electronics , Will the RC differentiator... differentiate like in mathematics Is THIS possible Vi = sin2wt , Vo = 2cos2wt .. mathematically differentiation of sin2wt will give 2cos2wt...... (Vo= differerential (Vi)) IF we design a RC diff ... to satisfy equation RC= 0.0016T where R and C are values of resistor capacitor respectively and T ( Time period of ...


Coil Circuit

Started by Anonymous in sci.electronics.design7 years ago 11 replies

Hi,=20 I am trying to make a wireless battery Charger. I made a coil ( primary coi= l) with following Specs 1. Number of turns :25 2. Wire...

Hi,=20 I am trying to make a wireless battery Charger. I made a coil ( primary coi= l) with following Specs 1. Number of turns :25 2. Wire Guage: 24AWG 3. Inductance : 426uH I added a series Capacitor with the coil. I am driving this LC series Circu= it with a Full H- Bridge driver ( HIP 4081A ) with four NMOSFETS. The power= supply is +12 Volts.=20 I am using Pulse Width Modultion...


A diode in series with a brushed universal motor?

Started by John Doe in sci.electronics.design7 years ago 5 replies

Not concerned about safety for this discussion. What will happen if you put a diode in series with a universal brushed motor? Of course...

Not concerned about safety for this discussion. What will happen if you put a diode in series with a universal brushed motor? Of course talking about a diode that can handle standard USA 120 V 60 Hz household power. Just putting a diode on one of the wires coming from the outlet, to rectify the current. Would a capacitor after the diode be useful? What sort of capacitor would be require...


Alternatives to capacitors from American Technical Ceramics

Started by Darol Klawetter in sci.electronics.design7 years ago 19 replies

I need a broadband chip capacitor (0.01uf) that has nearly ideal performanc= e up to 3 GHz. I'm using it to AC couple the RF input of a receiver....

I need a broadband chip capacitor (0.01uf) that has nearly ideal performanc= e up to 3 GHz. I'm using it to AC couple the RF input of a receiver. Americ= an Technical Ceramics manufactures capacitors (e.g., the 550 series) that h= ave excellent performance up to 40 GHz. Of course, this comes at a cost: th= ey are about 100 times more expensive than a standard x7r cap. I would like= to find s...


Question regarding diac-triac lamp dimmers

Started by Anonymous in sci.electronics.design7 years ago 8 replies

Could some electronics guru please hekp ? Maybe this is a stupid question, but here we go. Simple AC kine based lamp dimmers use a diac...

Could some electronics guru please hekp ? Maybe this is a stupid question, but here we go. Simple AC kine based lamp dimmers use a diac triac pair with a capacitor that gets charged via a resistor chain that includes a potentiometer to control the charging rate. When the capacitor gets charged, it discharges via the diac, and this in turn triggers the triac. So far so good. But t...