3 Small Power Transformers for Printed Circuit Boards Bonus: 6 Zener Diodes Primary: 100V / Secondary output, please refer to image 2. Even if the secondary is short-circuited, the primary current is small, and it cannot be protected by a fuse. However, considering other troubles such as primary side connections, we recommend a fuse of about 0.5A on the primary side. (No ignition occurred in the experiment with secondary short circuit) For the power supply of analog preamplifiers, etc. Can be easily configured with only Zener diode stabilization. ● Added 6.8V / 1W Zener diodes, which are included as a bonus, in image 4. ➕️➖️ power supply for 3 circuits, 6 pieces. (Bonus from experience in making tone control amplifiers and channel dividers) In addition, it can be easily used for power-saving, small-scale circuits. If you are capable, it may also be possible for the output transformer of a vacuum tube headphone amplifier, but NG for power amplification tubes! Those with technical skills, please try challenging a headphone vacuum tube amplifier. Old power transformers for communication terminals. Made in Japan, manufacturing year unknown. They have been stored in a sealed state. Multiple units are available. DC resistance measurement will be performed before shipping. The items to be shipped are not the ones in the image, but they are from the same production lot. ● No warranty! ● Please use at your own risk. #SmallTransformers #SmallPowerTransformers #MiniatureTransformers #MiniaturePowerTransformers #PreamplifierPowerSupply #OpAmpPowerSupply #SmallOutputTransformers #HeadphoneAmplifierPowerSupply #VacuumTubeOutputTransformers #12AX7 #6AU6 #CMOSPowerSupply #HCMOSPowerSupply Second time listing