Bridge Rectifier Problem.......!!!!!!!

Started by jo.jo in sci.electronics.basics11 years ago 21 replies

I am trying to construct a small desktop power supply and have noticed a small problem when measuring the output voltage from my...

I am trying to construct a small desktop power supply and have noticed a small problem when measuring the output voltage from my bridge rectifier. The rectifier is constructed from four 1N4001. When i apply a AC wave (sin) to the input and measure the output, using a oscilloscope, the bridge rectifier seems to produce only halfwave rectification. I was expecting full wave rectification. ...


Need simple 50V output stage for 4Mhz function generator

Started by royalmp2001 in sci.electronics.basics11 years ago 6 replies

I have a function generator that gives out upto 10V (0.1Hz to 4MHz). Need to add a simple output stage to provide upto 50V for this bandwidth...

I have a function generator that gives out upto 10V (0.1Hz to 4MHz). Need to add a simple output stage to provide upto 50V for this bandwidth (will provide dedicated power supply). Any suggestions for the configuration?


How to calculate a battery capacity

Started by Simon Dice in sci.electronics.basics11 years ago 9 replies

I'm working on a project in wich I need to have a system running 24hrs a day , power supply will be solar panels feeding a battery. Can any one...

I'm working on a project in wich I need to have a system running 24hrs a day , power supply will be solar panels feeding a battery. Can any one share with me formulas on how to calculate de Amp/hr for the battery and the power of the solar panel? Systems will consume average 80watts and need to keep running on a few clowdy days as well. Thanks for the assistance!


Choosing voltage opamp

Started by Vitaliy in sci.electronics.basics11 years ago 28 replies

Hello, I'm looking to add the 2nd stage to photodiode transimpedance amplifier. All I want to achieve by 2nd stage is voltage gain...

Hello, I'm looking to add the 2nd stage to photodiode transimpedance amplifier. All I want to achieve by 2nd stage is voltage gain and capability to drive 50 Ohm loads. The first stage is OPA657. 1) a) Given power supply for opamp +-5V, should I select the opamp that has Io,max=> 200mA. I do expect Vpeak-to-peak,output to be 10V. b) Is that output current achievable only at maximum sup


ULN2803A (darlington array) anyone know what I'm doing wrong?

Started by Ben in sci.electronics.basics11 years ago 14 replies

Applying 5V to the inputs (power supply is also 5V), I'm only getting 0.6V at the outputs. I thought it was a faulty chip, or perhaps damaged...

Applying 5V to the inputs (power supply is also 5V), I'm only getting 0.6V at the outputs. I thought it was a faulty chip, or perhaps damaged while soldering, but I've tried another one in a holder and got the same result. What could be causing this?


Connection Car Radio to a computer Power Supply ?

Started by Anonymous in sci.electronics.basics11 years ago 5 replies

Hey ! I'm trying to do that thing and I don't even know if it is possible ... Powering a car radio with a computer power supply ? - The...

Hey ! I'm trying to do that thing and I don't even know if it is possible ... Powering a car radio with a computer power supply ? - The Radio is powered by those : http://membres.lycos.fr/menusia/radio/DSC00796.JPG - Power Source from the 'inside' ( Sorry, not very clear ) http://membres.lycos.fr/menusia/radio/DSC00797.JPG For 1 Connector : "its actually 3 pins in the middle (white...


Switcher impulse noise reduction...

Started by Dave in sci.electronics.basics11 years ago 5 replies

Does anyone have any experiance removing the switching noise from the output of a switch mode power supply? I have tried in vain but...

Does anyone have any experiance removing the switching noise from the output of a switch mode power supply? I have tried in vain but think there is a way to actively filter it out somehow. We're talking about a 20mv peak to peak noise spike at ~ 60 KHz or so. A picture is worth a thousand words but I cant see a way to attach one in this group. Any help would be great! I tried this circui...


What is the proper way of setting up an oscilloscope?

Started by MRW in sci.electronics.basics11 years ago 15 replies

Hello there! I have an Instek GDS-2202 digital storage oscilloscope. I am trying to figure out how to setup my scope to minimize the pick up...

Hello there! I have an Instek GDS-2202 digital storage oscilloscope. I am trying to figure out how to setup my scope to minimize the pick up of stray 60Hz mains signal. If I change my scope's vertical sensitivity to 20mV/div, then I can see the 60Hz signal. The signal's amplitude increases even more when I turn on my DC power supply. I can pick this signal up without even connecting the pr...


Electric Kontiki motor power supply and PWM questions

Started by Anonymous in sci.electronics.basics11 years ago 22 replies

Hello, I'm finally getting around to building an electric fishing Kontiki and have some questions about how to do so. First off an electric...

Hello, I'm finally getting around to building an electric fishing Kontiki and have some questions about how to do so. First off an electric Kontiki is basically a timed torpedo with a prop either at the rear or more recently at under the front to take a line out past the breakers into deeper water where hopefully more and bigger fish lurk. I have a schematic I've drawn up at http://www....


ATX power supply to drive a 12V DC motor?

Started by MK in sci.electronics.basics11 years ago 44 replies

Hi, I have a 12V DC motor (6A under load). The only power supplies I have around here are ATX. Someone at an electronics shop told me they can...

Hi, I have a 12V DC motor (6A under load). The only power supplies I have around here are ATX. Someone at an electronics shop told me they can be used to supply the power, but I didn't ask how. Is it just a matter of using an IDE connector to power the motor? Regards, Michael


PSpice Models

Started by Irina in sci.electronics.basics11 years ago 1 reply

Hello all! I try to build a power supply. Therefore I would like to simulate my circuit with the student version of Pspice. I find some models...

Hello all! I try to build a power supply. Therefore I would like to simulate my circuit with the student version of Pspice. I find some models of voltage regulaters on the internet. Now I ask, if it possible to use these models with the limited version of PSpice. Has anyone of you put the model into the normal liberary? If yes, how can I do it? I would be happy about a fast response! ...


lab power supply

Started by duns...@gmail.com in sci.electronics.basics10 years ago 13 replies

hi to all i'm an italian electronics hobbyist, i'm sorry for my bad english :( in this holiday i try to build my first lab fully adjustable...

hi to all i'm an italian electronics hobbyist, i'm sorry for my bad english :( in this holiday i try to build my first lab fully adjustable power supply unit i try to hack the scheme at pag.8 of the datasheet of the lm317 http://www.ortodoxism.ro/datasheets/nationalsemiconductor/DS009063.PDF for add the negative section, the tracking voltage mode, the transistor for increase the output cu...


Power Supply Rectification and Smoothing

Started by Anonymous in sci.electronics.basics10 years ago 93 replies

I'm building a power supply for a 36V, 500W DC motor to drive a small lathe. I have scrounged a transformer from an old microwave oven and...

I'm building a power supply for a 36V, 500W DC motor to drive a small lathe. I have scrounged a transformer from an old microwave oven and removed the 2000V secondary windings leaving the 240V primary windings intact and undamaged (I will test with a megger before powering up.) I will wind some 30A automotive flex around the secondary core and test until I have around 36V (the rated volt...


Voltage controlled rheostat?

Started by Jonathan Busby in sci.electronics.basics10 years ago 18 replies

I'm no analog electronics expert by any definition of the word so I apologize if this question is stupid. I'm looking for a device ( preferably...

I'm no analog electronics expert by any definition of the word so I apologize if this question is stupid. I'm looking for a device ( preferably no assembly required ) that functions as the hypothetical device in the subject : something that takes a control voltage of 0-12 volts and adjusts the output from a voltage source ( a power supply ) from 0-24 volts linearly w.r.t the control voltage w...


Trying To Adapt Electrophoresis Power Supply for High Voltage Microamperage

Started by SMH in sci.electronics.basics10 years ago 3 replies

I have an urgent problem. The extent of my knowledge of electrical engineering is a trimester course in university physics in electricity and...

I have an urgent problem. The extent of my knowledge of electrical engineering is a trimester course in university physics in electricity and magnetism; I am molecular biologist/biochemist. We have some old electrophoresis power supplies we are using for a method called "isoelectric focusing." These power supplies have a load detection system in which the current must be in the MILLI...


power supply explanation

Started by F Murtz in sci.electronics.basics9 years ago 35 replies

This news group business is a hard path to tread what with cranky australians and americans with money and magical Radio Shacks that have just...

This news group business is a hard path to tread what with cranky australians and americans with money and magical Radio Shacks that have just what you want. Most of the replies were courteous and may have been helpful if I were into design My existing power supply I made over fourty years ago with some ca130 op amps and a 3055. I did not design the circuit [it came from radio and hobbi...


Really old homebrew power supply

Started by Paul E. Schoen in sci.electronics.basics9 years ago 5 replies

I have a power supply that I built as one of my first projects when I was in high school, in the mid 1960s, and it has always worked well enough...

I have a power supply that I built as one of my first projects when I was in high school, in the mid 1960s, and it has always worked well enough for my needs. It's in a Bud "Portacab" 6" wide, 8" high, and 8" deep. It has 2" analog meters, 0-10 VDC, and 0-3 ADC, and a ten-turn pot for output voltage adjustment. It has a 2 wire non-polarized lamp cord for AC supply, with a fuse on one of the i...


LPT port relay

Started by Test in sci.electronics.basics9 years ago 5 replies

I am trying to use LPT port to control a small 5 V relay (Meisei ps-5). The relay appears to have 1.75 ohm resistance. I connected the data...

I am trying to use LPT port to control a small 5 V relay (Meisei ps-5). The relay appears to have 1.75 ohm resistance. I connected the data pin to the + pin of the relay and ground to the gnd pin. No click. Voltage drops to about 2V. Then I tried with DC power supply at 4.5V (1.5A). A nice click is audible from the relay. (Bear with me: I am a newbie) I conclude that LPT is not suppliyi...


What range should my POT be?

Started by kayvee in sci.electronics.basics9 years ago 23 replies

Okay, so I have this motor and it is powered by a 24VDC power supply, and I would like to vary the voltage going to this motor. This motor draws...

Okay, so I have this motor and it is powered by a 24VDC power supply, and I would like to vary the voltage going to this motor. This motor draws 0.4A with 24V. I understand that connecting a pot normally to this motor will burn out the pot rather quickly, so one must use a NPN transistor. I reckon in this fashion: V+ ---+---------------+ | | P /c ...


schottky diode question

Started by tempus fugit in sci.electronics.basics8 years ago 10 replies

Hey all; I'm planning on using a MAX4622 CMOS switch in a circuit I'm building. On p.7 of the data...

Hey all; I'm planning on using a MAX4622 CMOS switch in a circuit I'm building. On p.7 of the data sheet (http://datasheets.maxim-ic.com/en/ds/MAX4621-MAX4623.pdf), it says: "If power-supply sequencing is not possible, add two small signal diodes in series with the supply pins and a Schottky diode between V+ and VL" I've read a bit about Schottky diodes, and I see that there are severa...