Barrie,
I guess you are using a transformer, rectifier, and filter capacitor. The capacitor is charging up to the peak value of the AC waveform. You could go all out and make nice DC with regulators, and such, but for relays do you really need that? If your rectifier is full wave then just remove the capacitor filter, and the rectified DC will likely be fine to energize a DC relay. A half wave rectified DC might not do too well since the relay might buzz away. It helps to put a diode across the coil (cathode to + end) to suppress the back EMF when you turn off the relay. Jim WD5JKO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Barrie Smith Sent: Saturday, March 18, 2006 6:47 PM To: Discussion of AM Radio Subject: [AMRadio] Voltage regulator This last week I built a 12 volt and 24 volt power supply in one small box to power various relays around the shack. Well, the 12 volt turned out to be 16 volts, and the 24 volt is 36 volts. Even loaded the voltage is high. I've done quite a bit of Googling on the subject of three-terminal voltage regulators, but have found nothing that had actual component values that would be pertinent to my needs. Also saw a three-terminal using a pass-transistor. Again, no actual component values. I'd like to be able to get the voltages down to more nearly what I need so that I don't burn out a relay. Perhaps 14 volts and 26 to 28 volts, at an amp or so. My knowledge of solid-state devices is close to zero. Anyone have some ideas? 73, Barrie, W7ALW ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.2.5/284 - Release Date: 3/17/2006 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.2.5/284 - Release Date: 3/17/2006
