I need 8 amps of 12 VDC power to operate several reels of LED lights. The only power supply in my toy drawer big enough to do the job has an issue with its regulating circuitry as it is currently outputting 14.2 VDC under load.
My understanding of proper operation is that Zener diode D3 provides a referencence voltage for SCR1 to do the heavy lifting of regulating the device's current. Last night D3 was replaced with a 12 volt Zener diode. With a small light bulb as load, the output voltage was still high. The Zener got quite warm even though the cathode voltage was reading about 12 volts.
I assume the SCR must be bad. If nothing else, it never warmed up the least little bit. Mail-order, a new SCR is around $16.
Out of curiosity, the plan tonight is took hook up a standard, incandescent wall dimmer out of my toybox to the power supply input to see if I can pulse-width-modulate my way into the proper output voltage.
Does anyone see a long term problem with the dimmer approach? Anyone think the base problem is not the SCR?
Thanks,
Tom
My understanding of proper operation is that Zener diode D3 provides a referencence voltage for SCR1 to do the heavy lifting of regulating the device's current. Last night D3 was replaced with a 12 volt Zener diode. With a small light bulb as load, the output voltage was still high. The Zener got quite warm even though the cathode voltage was reading about 12 volts.
I assume the SCR must be bad. If nothing else, it never warmed up the least little bit. Mail-order, a new SCR is around $16.
Out of curiosity, the plan tonight is took hook up a standard, incandescent wall dimmer out of my toybox to the power supply input to see if I can pulse-width-modulate my way into the proper output voltage.
Does anyone see a long term problem with the dimmer approach? Anyone think the base problem is not the SCR?
Thanks,
Tom
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