Posted on Sunday, January 6, 2013 • Category: Power Supplies
12V dual power supply has symmetrical voltage output +12V and -12V with limited current to 100mA. It has been built to power three OPA627 opamps of Audio DAC I am building with PCM1792 & PCM1794 chips. Circuit has on the primary side only fuse. I couldn't find smaller than 50mA. We can connect power cord directly to the X1 connector or via power switch on the chassis. On the secondary side of transformer are connected two fuses 100mA and after them is bridge rectifier. For filtering of rectified voltage there are C1 and C2. Next are positive and negative voltage regulators 78L12 and 79L12 with decoupling capacitors C3 to C6 close to regulators. Next are small filter capacitors and also signaling LEDs connected via resistors. Output voltages are connected to 3 pin connector. For signaling of presence of voltage is enough only one LED. We can also use 2 pin connectors for LED connecting.
Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]
