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Half wave the 3VAC with a single diode 1n4001 is OK. That will give you about 1.5 V equivalent pulsed DC. However if you accidentally move the tap to a higher voltage (easy to do on the power chief) you can burn out the bulbs.

Another way is to get a small bridge rectifier. Connect the + and - and put the 2 AC leads (marked ~) in series with any light bulb on the layout. For example a street lamp run on 14 volts. When the street lamp is powered it will receive 12.8 volts. Tapping the 2 AC leads of the bridge will yield 1.2 VAC whenever the street lamp is on. Hook this to the 1.5 volt bulb(s). This is burnout proof regardless of transformer voltage.

Dale H


Dale,
Re your post on this subject, I made some circuit diagrams to go along with your text. Are they correct?
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Bob, in the top drawing the bulbs would be in parallel as output effectively is 1.5 volts RMS DC from the diode (ignoring the forward .6 volt drop). In the bottom drawing the bridge rectifier serves no purpose as the series wiring distributes half voltage to each bulb (assuming they are identical). Another way I described was to take a bridge rectifier with the + and - connected and place it in series with a load ( the 2 AC leads marked ~),such as to a lamp post for example. Tapping these 2 leads will clamp about 1.2 volts whenever the load goes through the rectifier (when the lamp post is lighted,for example). 2 rectifiers this way in series would clamp about 2.4 volts. This is useful in lighted cars needing marker lights or installing directional lighting in locomotives.

In this example below in the link where the paired diodes are in series with the motor circuit

http://www.jcstudiosinc.com/Bl...d=488&categoryId=426

5 paired diodes would clamp + or - 3VDC whenever the motor(s) is running,polarity depending on train direction. Tapping this with a 3 volt bulb would give non directional lighting. With a blocking diode it could be made directional. Tapping it with an LED would give directional lighting.

Dale H
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OGR Publishing, Inc., 1310 Eastside Centre Ct, Ste 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

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