Pulse-Generator & Signal-Tracer with BC547,BC557| Circuit Project

Dual-purpose test-instrument Very simple circuitry, 1.5V Battery-operated

This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. A high-pitched tone can be heard from the speaker of the device under test when all is working properly. The clip must be connected to the ground of the device under test, touching with the probe the different stages of the circuit, starting from the last stage and going up towards the first. When the tone is no longer heard, the defective stage has been found. [...]

Parts:
R1__________________1M 1/4W Resistor
R2,R4_______________2K7 1/4W Resistors
R3________________150K 1/4W Resistor
C1__________________2n2 630V Ceramic or Polyester Capacitor (See Notes)
C2,C3_______________4n7 63V Ceramic or Polyester Capacitors
D1_______________1N4148 75V 150mA Diode
Q1________________BC547 45V 100mA NPN Transistor
Q2________________BC557 45V 100mA PNP Transistor
SW1________________SPST miniature Slider Switch (See Notes)
J1_________________Stereo switched 3mm. Jack socket (See Notes)
Probe______________Metal Probe 3 to 5 cm. long
Clip_______________Miniature Crocodile Clip
B1_________________1.5V Battery (AA or AAA cell etc.)

Read More Source: http://www.redcircuits.com//Page59.htm
Thank you.

This entry was posted on Monday, September 10th, 2007 at 10:25 pm and is filed under Circuit diagram, meter.

Circuit diagrams and schematics - Electronic projects

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Pulse-Generator & Signal-Tracer with BC547,BC557