Finding the right relay - Page 2 - Electronic Circuits Projects Diagrams Free

1y5zdzjy · 10th June 2009, 06:12 PM

Quote:

Good engineering practice requires five additional resistors from each PNP base to +5V to guarantee that the PNPs will turn off.

That is incorrect.

Quote:

Additionally, your circuit makes a big assumption that there is a pull-down resistor on each of the inputs to the PC interface, so that the input signal is at a defined "LOW" when the PNP transistor is off.

Yes it does make that assumption, based on what dranobob said "When 5v dc is applied to an input, the controller sends a signal to the software in the computer."

2N3906 (TO92) or FMMT591 (SOT-23) will both work for the transistors.

Mouser Electronics - Electronic Component Distributor is a good place to order parts in the US.

dranobob · 10th June 2009, 06:35 PM

considering I can't even get totals over $2 I'm going to build both setups

Try em both and see which I like best. Even if they both work perfectly....I used to love to build circuits and been way too long....will be fun

dranobob · 10th June 2009, 07:20 PM

question can you order small boards to solder the components to? I remember using the bread boards back in college, but I'm looking something about 2" square.

1y5zdzjy · 10th June 2009, 07:34 PM

Mouser Part No: 589-7100-45

dranobob · 10th June 2009, 07:55 PM

thanks, everyone has been awesome, I can't wait to start soldering, figure 3 or 4 days to get the parts!

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10th June 2009, 06:35 PM	#17
dranobob	considering I can't even get totals over $2 I'm going to build both setups Try em both and see which I like best. Even if they both work perfectly....I used to love to build circuits and been way too long....will be fun

10th June 2009, 07:20 PM	#18
dranobob	question can you order small boards to solder the components to? I remember using the bread boards back in college, but I'm looking something about 2" square.

10th June 2009, 07:34 PM	#19
1y5zdzjy	Mouser Part No: 589-7100-45 __________________ Circuit design

10th June 2009, 07:55 PM	#20
dranobob	thanks, everyone has been awesome, I can't wait to start soldering, figure 3 or 4 days to get the parts!