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 is not possible to protect it with a fuse. However, considering other troubles such as primary side connections, we recommend a fuse of about 0.5A on the primary side. (In experiments, short-circuiting the secondary did not cause ignition) For the power supply of analog preamplifiers, tone control amplifiers, etc., it can be easily configured with only Zener diode stabilization. Also convenient for the power supply of low-power consumption microcomputer small-scale systems! ● Added 6.8V / 1W Zener diodes as a bonus, shown in image 4. Simple stabilized power supply can be configured. +7V, -7V power supply for 3 circuits, 6 pieces. (Bonus from experience in making tone control amplifiers and channel dividers) Other applications, can be used easily for power-saving, small-scale circuits. If you are capable, it might be possible to use them as output transformers for vacuum tube headphone amplifiers? NG for power amplifier tubes! Those with technical skills, please try to challenge a headphone vacuum tube amplifier. Power transformers for communication terminals, old ones. Made in Japan, manufacturing year unknown. They have been stored in a sealed condition. 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 them at your own risk. #Small transformers #Small power transformers #Small transformers #Small power transformers #Preamplifier power supply #Op-amp power supply #Small output transformers #Headphone amplifier power supply #Vacuum tube output transformer #12AX7 #6AU6 #CMOS power supply #HCMOS power supply #Microcomputer system power supply #Microcomputer power supply Third time listing