• 1x dc blocking capacitor(10nF to 10uF) C3(2.2uF Axiel Film Capacitor)
• 2x 100nF Capacitors C1 and C2
• 2x 1k ohm resistors R1 and R2
• 2x 4.7k ohm resistors R3 and R4
• 2x General Purpose NPN low power transistors Q1 and Q2(I used PN2222A)
• A 1.2 to 14v dc power source
• A alligator ground clip

This signal injector can come in handy for repairing radios, amplifers and old TVs and also square wave generator in a probe. Later on I will make a version that uses C1 and C2 as 470nF and R3 and R4 as 1 Megaohm and C3 as 47uF(Since the frequency is ultralow).

The specs

Where R=R2 or R3, C=C1 or C2 and \(C_{3}\)=C3

Frequency: \(f=\frac{1}{1.38RC}=1.5kHz\)

Output AC Resistance: \(X_{C3}=\frac{1}{2\pi*fC_{3}}\)

PCB Files

The post Basketball pump signal injector first appeared on Delphijustin industries.

That circuit above makes it act like an Uninterruptable Power Supply(UPS). I drilled four holes into th battery cover so I could use the cover as a Circuit board for the diodes.

The post Powering a Scanner from a power supply and battery pack at the same time first appeared on Delphijustin industries.