I usually use a 2N3904 NPN transistor ... or the PNP equivalent 2N3906 ...
Neil - WA6KLA Gary La Force wrote: > I have done the same thing but have used a 7404 TTL level inverter. > But if your COS level goes any higher then about 5.5vdc you will blow > the 7404. I also like using the NTE2358 Digital transistor it has all > the bias resistors build in and is a snap to hook up and put in > service. > > Gary N0PBM > > -----Original Message----- > From: Richard [mailto:[EMAIL PROTECTED] > Sent: Friday, November 14, 2003 8:52 AM > To: [email protected] > Subject: RE: [Repeater-Builder] COS Logic Circuit > > That circuit actually should work fine. All it is doing is reversing > the logic of your COS signal. When COS is present (+5V), 0V will be > present at the output, +5V will be at the output when COS is not > present. > Richard, N7TGB > > -----Original Message----- > > From: Bruce Morgan [mailto:[EMAIL PROTECTED] > Sent: Thursday, November 13, 2003 7:59 PM > To: [email protected] > Subject: [Repeater-Builder] COS Logic Circuit > I have a question about logic circuits. I have a Yaesu FT > 1500 that has the data port on the back and I want to use > the 1500 as a temporary receiver in my repeater while the > acutal receiver is out for repairs. Here is my problem, the > data output port has a COS pin out (Carrier=5 volts, none = > 0 volts) My contoller port says, Receive COS (pull this > input low when receiving). > So I need to turn my positive logic signal to a negative > logic signal. I found this circuit to do the the opposite > of what I need ( > http://www.repeater-builder.com/pix/cosswitch.gif ) Can I > and if so how can I modify this to produce the positive > logic with no signal and negative logic when a carrier is > present. > Or is my line of thinking completely out of line? > > Thank you. > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service. > > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. > > > > > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
