Compact logic probe with housing
Compact logic probe with housing

Logic probe is an essential item for digital electronic fault findings and constructions. In this project we design compact and simple logic probe with digital pulse generator. This circuit is based on 4069 logic inverter and 7805 voltage regulator. In this design we use 4069 invert module to drive the LED of logic probe and to build the oscillator circuit.

We use TO-92 style of 7805 regulator to drive the 4069 chip and entire circuit can be build around 2.5cm x 12cm PCB (if you need to reduce the size in to more, use the SMD version of 4069 and 7805)

All the resistors are 1/8w and SMD versions are also acceptable.

To change the period of pulser modify C1 or/and R2.

Project Related Downloads

Complete schematic of "compact logic probe with pulser"


CD4069 - Hex inverter
LM7805 - 3 Terminal Positive Voltage Regulators