badai

I have serial cable consist of 4 ports(on pcb).........one of them cannot work(physical problem). My expectation is because of the IC on that port. So, how i can know this is because of IC problem? Is it enough to test it using multimeter and compare with other IC from different port??? Any idea

AA215 diode I used for the design circuit only. The real diode is 1N34A. How to calculate the gain defined by C8,R6 and R12? What does it means, VCO that operates out of frequency range? What is the purpose of TR3, is it used as amplifier too? Why it need used 4.7k

so what minimum frequency it shoul be detect? How the VCO in this circuit is formed? Is it same like in tune radio circuit? :-\

actually i had finished my layout. i export the layout in bitmap file but the problem is the size become larger when i want to print it. how to make it actual size? i try print directly(without export) and i got the real size but it was positive layout. my lab can do only negative layout. how to setting this one...pls.... :-\

as in datasheet if i'm using 2N2222 as my TR1, min. freq it will detect is 250MHz, so what is the maximum frequency(frequency range)?

how to calculate the cut-off frequency which has value 60Hz?

this is my latest schematic but still missing R17....... :-\

can you show me clearly which part i should place R17?

(no components)

layout on board

this is the original one

if that kind of problem, i hope it can detect up to 200MHz until 300MHz, so i can use 2N2222 in this circuit isn't?

as you ask MP, i move to this forum. It looks like the author missed R17 on his schematic, from pin 12 to ground like R23 on the other side.(AUDIOGURU said).....can you show me clearly, where it should be placed? ERROR: Sheet 1/1: no SUPPLY for implicit POWER Pin IC1P V+ ERROR: Sheet 1/1: no SUPPLY for implicit POWER Pin IC1P V- how should i do with this connection? i know this connection for PIN 4 and PIN 11, so how to draw this part? Pad 1 for antenna is it right? so can you comment what is still not cover or something wrong in my circuit and hopefully no more problem after this.

hello guys. i am doing stepper motor control for position and velocity( ramp generator) .i am using 8051 as the microcontroller. anyone know how to construct ramp generator for stepper motor? how is the connection then? does it an external circuit to the motor or it has to be connected to my 8051? a simple current could be use the, how the circuit is and how to connect it?

1- i just scatch back, is it like this you mean? 2- So if the phone operates up untill 1900MHz, which one is appropriate transistor(except BFR90A) from list you given? 3 - In my previous circuit ff i'm using pad 1(wirepad) to connect my antenna, is it will work for my antenna?

i hope it can detect rf signal from cell phones. so up to 200MHz or 350Mhz it's okay for my circuit.

where is R17? i didn't find it in circuit diagram but this component had been placed in layout board , is it missing? this is my schematic circuit. can you check for me either right or not? i'm using pad 1(wirepad) to connect my antenna, is it right? why my +ve and -ve(supply symbol) point not occur in my layout?

i'm thinking of designing an FM transmitter and receiver that have the carrier frequency around 200MHz using no IC but i could not find the circuit schematic. help needed ???

thanks so much for helping me......... ;).......now i understand to use this software....and hopefully can improve better after this.....actually i can't get this component (BFR90A) in my local shop, i bought wrong component actually before this....another series (BFG90, BFQ28, BFR24, BFR49) also didn't find. what should i do now????

i'm not so sure the symbol for potentiometer(P1), i'm choosing PC16S but it has pin E, S and A. which one should connect with R12?

after i finish design schematic using EAGLE, i click to BOARD button, then i follow the instruction but when i clcik AUTO button, EAGLE cannot perform this command but on my schematic no error and warning was found. What is the problem? i didn't found this diode symbol BA481(OR NTE112) in library, so how should i do?

another one is all the grounded components should be connected together to pin 11 isn't it?

for R13 at the +ve point it should be connected with pin 4 for IC1. is it right?

I'm using eagle editor layout.......for BFR 90A what kind the symbol should i use from library because this transistor not same like common NPN transistor but the symbol from circuit given same like NPN transistor

actually i'm a beginner user for EAGLE Layout Editor, so I'm not sure either i draw the layout right or not. Can you send me the pcb design(electronic eavesdropping devices detector), so i can send directly the transparent directly to pcb lab at my faculty?