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Pop the case screws and tell us what you see?

Since TOPICS have been DEAD lately, thought I'd share a tip...<p>I wanted an "Electro-Chromic-Rearview-Mirror" (electronically dims when your tailgator has his brights on); $250 dealer, $25 salvage. But it was HEAVY --- mount promptly fell off the windshield. And then at least once a year ...

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Connect a 0.1uF capacitor from pin 2 to the junction of the dash-mounted light and the switch which grounds it. <hr></blockquote>Exactly how I woulda wired it. 555 is NOT "edge triggered",...

Couple hundred. Unless you're talkin' about the CMOS version, 7555; I don't remember, think it's 100 max...

I have a unit from "Rocky Mountain". Actually, I have TWO of them --- ordered a second one 'cause it said it also jams LASER. There's not alot to them, the LASER just adds one resistor and one infra-red emitter. The entire circuit is an 8-pin-Pic chip, which outputs a simple audio tone, on...

Aha! Someone's been driving with the parking brake on! Back when I was in high school, I was in the MARCHING BAND; one trip, a gas-station-attendant came running out to one of the school busses shouting, "HEY! Do you know you have FLAMES coming from under the BUS???" Driver had left the br...

OH if you use a DARLINGTON transistor, your capacitor will see a volt and a half max. Electrolytic capacitors have a bad habit of drastically changing capacitance over time if they are severely under-voltaged...

You won't get simpler than one transistor, one resistor and one capacitor. Use an NPN with sufficient power to drive your relay, emitter tied to ground; then tie the base HIGH with a resistor (limited by your relay current, divided by transistor current gain --- a 10k resistor will provide ~1 mA, if...

I would suggest BUYING a cheap headset and cannibalize them. I bought a set of 18-25000hz at Big Lots for about $4...<p> May I suggest you find headphones rated at 15hz - 25khz or better? If you buy 20-20k, odds are they are LYING, and just GUESSED at the frequency; but even if TRUE, those two point...

Filters are a good idea, but a new power supply might be simpler. Current draw on the CD player should be quite low, lending itself to a linear regulator. These can be bought for $7 - $15; they contain some way of selecting the output voltage, usually a slide switch. There is a way to choose the cor...

"We must know. We will know."<p> @ Analogee...

No-vice, you seem to be talking about an ACTIVE device --- as in "jammer". The VCD-42 is PASSIVE; it's merely a receiver . The point is that this will inform you of any electronic device nearby that contains a 15,750 oscillator; 'cause such a device will be some kind of VIDEO circuit . By ...

I received the VCD-42 today. As with most of what I own, the screws came out within the first couple of minutes. I found --- a simple ferrite bar, length about 4 inches, with a single coil around it. Hot-glued to the board. Looks like the inductor is paralleled with a poly-styrene capacitor --- unma...

A "Hall Effect Sensor" produces a voltage in the presence of a magnetic field. You could build one of the circuits from the internet, like this 555-based one , or you could build this one . The SECOND should easily interface to a Radio Shack digital recording/playback module. The trophy ne...

In my "grubby little hand" are some 50 pieces of LM3909 LED flasher. They cost me under 4 bucks each, including shipping, tax, gratuities, hamster charges, etc. Has anyoe here been looking for one of these? AS YOU KNOW they were obsoleted recently by NS. There are SO MANY CIRCUITS you can ...