All in One Tester Circuit - Engineering Projects

All in one multi-tester is quite expensive which may not affordable for every electronics beginner. Now, here is s cheap all-in-one tester circuit that can be used to test the condition of almost all the electronics components from the basic resistors to advance ICs. The circuit all in one tester is used to detect polarity, continuity, logic state, and also activity of multivibrator.

Description of All in One Tester Circuit

The circuit of the all-in-one tester is so simple that it can also understand by beginners. The circuit of all in one tester contains two transistors and very few other passive components. Transistor T₁ and T₂ are used here as a switch, driving the one half of bicolor LED each in order to give the result of the test.

Initially, the circuit is in off mode, when switch SW₁ is pressed, transistor T₁ stops conducting due to a lack of forwarding bias. At the same time transistor, T₂ takes base bias voltage from the battery through resistor R₁ and conducts. This allows the red half of bicolor LED₁ to illuminate.

Transistor T₁ conducts when the positive voltage through resistor R₃ is given to the base of transistor T₁ and lights up the green half of LED₁. In the conduction of transistor T₁ transistor, T₂ turns off and vice-versa.

Thus from the description, we know that the functioning of the circuit thus depends on the signal obtained at the base of transistor T₁. The table below gives the testing procedure for various components with the expected indication or result.

Bi-Color LED Status for Various Tests
Component/test	Test Procedure	LED₁ Status	Result	Note
Continuity	Red and black probes to the test points	Green ‘on’	Continuity
		Red ‘on’	No continuity
Polarity	Red probe to the positive of the circuit and black probe to the test point	Green ‘on’	Positive	The circuit should be ‘on’
		Red ‘on’	Negative or no power
Logic	Red probe to the circuit’s positive and black probe to the output	Green ‘on’	High	The circuit should be ‘on’
		Red ‘on’	Low
IC	Red probe to the circuit’s positive and black probe to the output	Green ‘on’	High	The circuit should be ‘on’
		Red ‘on’	Low
Multivibrator IC 555	Red probe to the circuit’s positive and black probe to the output	Color changes from red to yellow to green clinically	IC oscillating	The circuit should be ‘on’
		Red ‘on’	No oscillation
Electrolytic Capacitor	Red probe to the positive and black to the negative lead	Green gradually turns red	Capacitor good	The capacitor should be discharged
		Red ‘on’	Capacitor faulty
Diode (LED/Photodiode/IR diode)	Red probe to the anode and black probe to the cathode	Green ‘on’	Good	1 kilo-ohm resistor should be connected to the anode of LEDs
	Red probe to the cathode and black probe to the anode	Red ‘on’	Good
	In both conditions	Color remains the same (either green or red)	Open /short
Resistor (1 ohm to 500 Kilo ohms)	Red and black probes to the ends of the resistor	Green ‘on’	Good
		Red ‘on’	Faulty
Transistor	Red probe to the base of the transistor and the black probe first to the collector and then to the emitter	Green ‘on’ and again green ‘on’	Transistor conducts	The circuit should be ‘on’
	Black probe to the base of the transistor and red probe first to the collector and then to the emitter	Green ‘on’ and then red ‘on’	Transistor doesn’t conduct

Check out other various testing circuits posted in bestengineeringprojects.com

PARTS LIST OF ALL IN ONE TESTER CIRCUIT

Resistor (all ¼-watt, ± 5% Carbon)

R₁ = 1.8 KΩ

R₂ = 1.5 KΩ

R₃ = 4.7 KΩ

Capacitor

C₁ = 1 µF, 16V (Electrolytic Capacitor)

Semiconductors

T₁, T₂ = BC548 (General Purpose NPN Transistor)

D₁ = 1N4001 (General Purpose Rectifier Diode)

LED₁ = Bi-color LED

Miscellaneous

B₁ = 9V battery

SW₁ = on/off switch

3 Thoughts to “All in One Tester Circuit”

Manoj

February 21, 2015 at 12:33 pm

In 741 op-amp circuit tester, All the OP-AMP IC’s can be check

1. Engineeering Projects
  
  February 21, 2015 at 5:55 pm
  
  If you can manage their pin then, you can check almost all op-amp IC
  
Sevien Valencia

December 15, 2016 at 4:42 pm

can you give me the specific components in the handy tester? Thanks