that depends on a couple things, more than the 'btu rating' i.e: what are the sustained / peak power ratings on the inverter? what are the nominal / peak requirements of your AC unit? if the sustained power requirement of your AC unit is less than the output from your inverter, then it will possibly work. You also need to make sure peak requirement is less than the max your inverter can
Forum: Voltage Inverters

What kind of post is this? Send you the project? The project (schematic) is right here in the thread.. You want me to make the circuit and email it to you, components and all? That's ridiculous. You should really try making the project yourself and if you have legitimate difficulties with the circuit, or the circuit theory then post a question nandish Wrote: ----------------------------
Forum: Sound Detectors

Hey, what schematic are you using -- would you mind posting it? Does it have audio support? I'm afraid I don't have any UHF tv transmitters in my collection.. Though I do have vhf.. -andrew Nia Wrote: ------------------------------------------------------- > Hi there > I have a problem with my transmitter UHF I can't > to add a sound in the transmitter what can I do? &g
Forum: RF transmitters

Hey, I'm sorry for not getting back to you earlier.. If you're still around I'm interested in talking about that problem... I'd guess that the problem could be: a) using the wrong voltage terminals from the power supply b) the power supply is newer, and has to be turned on via a digital signal c) polarity is backwards on your circuit (not sure if this is possible) d) the solenoid is not
Forum: Comments, Suggestions, Conversation

about a year late, but the reason why there is no receivers section is because I haven't run across any radio receiver schematics. if you have ended up building one please feel free to post it.
Forum: Comments, Suggestions, Conversation

Hi, thanks for the nice words about the site -- if you can think of ways for me to improve it please let me know. meanwhile, sorry but I haven't worked on building any high-fidelity amps like you're talking about. good luck, -andrew p.s. sorry for late post
Forum: Comments, Suggestions, Conversation

Hey, do you mean you added decoupling capacitors? i.e. from the + rail to ground, and the - rail to ground? what sortof distortion are you getting in the music, weird humming or clipping? proper (generally very small picofarad) decoupling capacitors can take out noise introduced by the supply voltages. also, did you make sure to match the impedance on the input of your circuit with the
Forum: Comments, Suggestions, Conversation

here's the first email i'm posting, any comments/guidance is appreciated:: ----------------- from ehiunno Quote I see the preamp is labeled for use with an electret microphone, but the application im working on requires the amplication of a low-level source(namely, an ipod) a small amount as the headphone out doesnt put out at line-level. Could i use this pre-amp in this application? It as
Forum: E-mail Bag

Forum: Comments, Suggestions, Conversation

Forum: Comments, Suggestions, Conversation

testing smilies
Forum: Comments, Suggestions, Conversation

c2 is coming off of pin 5
Forum: Ultrasonic

Hey, Well, there are two things you could do.. You could find a 7.2v rechargeable battery back (they make these) or you could find/make a 7v regulator. rechargeable cells are generally 1.2v (opposed to non-rechargable cells that are 1.5v) a really cheap way of regulating the voltage would be by using a reverse biased zener diode across the terminals of the battery. This would probably be a b
Forum: Other

Hey Kevin, It would be possible to substitute a regular old resistor in place of the variable resistor, but that would require some derivations, and it would depend on what type of transistor, resistor tolerances, etc. If you calculated it you'd probably get close (a couple volts) but it is way easier to use a variable resistor and an adjustable power supply: set the power supply at around 9-1
Forum: Battery Power Monitors

I've never heard of an electric fly swatter, could you elaborate?
Forum: Miscellaneous

hey, i've added the avatar you wanted to the list of available avatars
Forum: Miscellaneous

for analog phones, you just need a radio tuned into the right frequency. for newer landline cordless phones they're both digitally encoded, and they change frequencies often, according to a pre-configured pattern. for analog cell phones, it's the same thing. you need (illegal to procure in the USA) radio that can tune to the right frequency. digital phone calls are encrypted & modulated t
Forum: Telephone

the forum was down for several weeks because a security issue. it's back up now.
Forum: Comments, Suggestions, Conversation

Sure you can use an oscilloscope :-D (not everyone has these though.. hehe I have $10,000 flat screen o-scopes at my school tho :-P) Connect the o-scope probes to pin 3 and ground. You should have a nice little squarewave trace on the o-scope. If your scope has a button that measures period or frequency, click it and see what the circuit is oscillating at. have fun, -andrew
Forum: Infrared

there is no E1 in this schematic. There is a P1 though. P1 is a AC cord into the wall.
Forum: Miscellaneous

Hey, actually I think this circuit will not give you any more voltage than you supply the 555 timer chip with. the 555's have an opamp inside of them, and that's how the op-amps work.. you can pick up these 555 chips at radioshack as well. I don't think there's anything wrong with connecting different battery sizes together in series. I think to actually double the voltage beyond what you ha
Forum: Voltage Doublers

Yeah, this is tricky because you can't tell if the IR emitter isn't right, or the IR tester isn't right. I've built both circuits and they work together. Also make sure the LED on the tester isn't in backwards. -andrew
Forum: Infrared

Uhm... Well if the circuit actually works as an inverter (I haven't tested it) then no modifications are necessary. It'll invert whatever you supply it with.. You could also use an opamp to invert your voltage. I don't know how good an idea it is. But just make sure the ratio of the two resistors = 1. (make them the same voltage....) such as in the schematic on this page:
Forum: Voltage Inverters

could have? sure. I'm sure it's fine though.. you can use the voltmeter to check. -Andrew
Forum: Infrared

by the looks of the schematic, the led and phototransistor/resistor should have similar packaging. if that's true, then the lenghts of the pins should be the same as the led. on led's usually the flat side of the package marks the cathode (band side of the schematic symbol) and that should be the shorter negative side. the longer pin should be the positive anode side. unfortunately this isn't
Forum: Infrared

Ah, thank you. topic is now moved
Forum: RF transmitters

Ah, thank you. topic is now moved
Forum: Amplifiers

oh.. wow.. good call -- thanks for pointing that out. I'll need to update the schematic and make sure everything's right.. pin 4 must be grounded, and pin 8 must be connected to +vcc (about +5v)
Forum: Sound Generators

Here goes, When powered up, electricity flows through r2, r3, and also through the path through r1 and the led's.. If no light is shining then the resistance of the photoresistor is high, so it blocks electricity from flowing into the ground. In this case, the electricity flows to the base of the transistor, and allows electrity to complete a circuit through the first path (r1, led's) to the g
Forum: Miscellaneous

well it is sortof.. problem with geocities, is they don't want people using their servers to host content for other websites (hmmm.. kinda like this situation.) if you just copy the link, and past it into a new browser window it should work. if not, then go to geocities.com and then paste in the address.. -andrew
Forum: Ultrasonic