Search found 341 matches

by Ron H
Fri Apr 26, 2002 8:27 am
Forum: General Discussion
Topic: Computer Monitor
Replies: 6
Views: 2802

Re: Computer Monitor

A shorted capacitor (the one that exploded) will do this if you defeat the fuse. Capacitors sometimes develop an internal short for no apparent reason. Replacing the capacitor may solve your problem.<p>Ron H
by Ron H
Mon Apr 08, 2002 6:48 am
Forum: General Discussion
Topic: Cellular Antenna Lights - I'm confused
Replies: 8
Views: 3386

Re: Cellular Antenna Lights - I'm confused

Well, I can believe that there is enough RF present during transmit to light an LED. In fact, I thought of that before I composed my last reply, but the fact that they apparently only light when receiving a call threw me off. I guess there is a handshake transmission that occurs before answering, an...
by Ron H
Sat Apr 06, 2002 7:13 am
Forum: General Discussion
Topic: AutoFade in/Out W level control circuit needed
Replies: 3
Views: 1846

Re: AutoFade in/Out W level control circuit needed

Russ, the circuit the OP referenced uses analog switches. It's hard to fade using an analog switch, unless you slow down the drive to the control pin. I also got the impression that he doesn't have the expertise to design his own circuit.<p>I just discovered that the URL I posted only takes you to t...
by Ron H
Fri Apr 05, 2002 3:02 pm
Forum: General Discussion
Topic: Cellular Antenna Lights - I'm confused
Replies: 8
Views: 3386

Re: Cellular Antenna Lights - I'm confused

OK, here's my rationale: I don't know the specs for a cell phone receiver, but a good radio receiver has a sensitivity of a few microvolts (or less), so I'm assuming that cell phones are similar. With typical antenna impedances, this translates to a few picowatts of received power. An LED requires a...
by Ron H
Thu Apr 04, 2002 8:24 am
Forum: General Discussion
Topic: cell phone antenna light thingies
Replies: 13
Views: 6063

Re: cell phone antenna light thingies

The LEDs light when a call is received, but they are not powered by radio waves. They are powered off the phone's battery.<p>Ron H
by Ron H
Mon Apr 01, 2002 10:05 am
Forum: General Discussion
Topic: circuit help
Replies: 10
Views: 4181

Re: circuit help

This is basically a good idea, but it might not work, due to setup and hold time requirements. The '373 latches on the falling edge of the enable input, and by the time it sees this edge, the input has already gone back high. A '374 should work in place of the '373, but I would add a couple more inv...
by Ron H
Mon Mar 18, 2002 6:37 am
Forum: General Discussion
Topic: RAM Memory chips
Replies: 2
Views: 1896

Re: RAM Memory chips

http://www.freetradezone.com/design_cen ... 208721.pdf<p>[ March 18, 2002: Message edited by: RonH ]</p>
by Ron H
Thu Mar 07, 2002 7:42 am
Forum: General Discussion
Topic: Looking for Trident Video drivers
Replies: 2
Views: 1571

Re: Looking for Trident Video drivers

Have you tried the 8900C driver?
http://www.tridentmicro.com/drivers/dow ... a8900.html<p>Ron H
by Ron H
Wed Feb 20, 2002 11:23 am
Forum: General Discussion
Topic: momentary signal to a shift register - how?
Replies: 9
Views: 3344

Re: momentary signal to a shift register - how?

You need a monostable multivibrator, also known as a one-shot. You can make one from a 555 timer IC, or there are various TTL one-shots available, such as 74121, 74123, 74221, etc. Look at http://www.fairchildsemi.com/an/AN/AN-366.pdf and at http://www.uoguelph.ca/~antoon/gadgets/555.htm for more in...
by Ron H
Wed Feb 13, 2002 8:57 am
Forum: General Discussion
Topic: electronic govener for gas engine
Replies: 29
Views: 11850

Re: electronic govener for gas engine

I apologize, Toejam. I totally missed the part about the pulses coming from the ignition sysyem. I agree that you should be able to get speed regulation from this type of system. The degree of regulation, I guess, would be dependent on the mechanical advantage built into the solenoid/spring/throttle...
by Ron H
Wed Feb 13, 2002 7:53 am
Forum: General Discussion
Topic: electronic govener for gas engine
Replies: 29
Views: 11850

Re: electronic govener for gas engine

Toejam, what provision have you made for increasing power to the throttle solenoid when the load on the engine increases? In the absence of a governor, a throttle simply provides (relatively) constant fuel flow at a given setting. As the load on the engine changes, the fuel flow requirements change....
by Ron H
Wed Feb 13, 2002 6:31 am
Forum: General Discussion
Topic: electronic govener for gas engine
Replies: 29
Views: 11850

Re: electronic govener for gas engine

Toejam, you have just (re)invented an electronically controlled throttle. It will work fine until the load on the engine changes. What's missing is a feedback loop which compares the engine RPM (or generator frequency) with a reference, amplifies and filters the error, and modulates the throttle to ...
by Ron H
Tue Feb 12, 2002 8:42 am
Forum: General Discussion
Topic: electronic govener for gas engine
Replies: 29
Views: 11850

Re: electronic govener for gas engine

Harold said:<p>"By the way guys, an eight bit subtraction is 256 parallel XOR operations. A = x - y is a universal control system. If everything was numeric, you could substitute a thermostat control from the hardware store."<p>OK Harold, I'll bite: (1) Since when does 8 bit subtraction require 256 ...