Showing posts with label Tester. Show all posts
Showing posts with label Tester. Show all posts
Tuesday, October 28, 2014
TRANSISTOR TESTER 1
TRANSISTOR TESTER - 1
Transistor Tester - 1 project will test all types of transistors including Darlington and power. The circuit is set to test NPN types. To test PNP types, connect the 9v battery around the other way at points A and B.
10mH choke with 150 turns for the secondary
The transformer in the photo is a 10mH choke with 150 turns of 0.01mm wire wound over the 10mH winding. The two original pins (with the red and black leads) go to the primary winding and the fine wires are called the Sec.
Connect the transformer either way in the circuit and if it does not work, reverse either the primary or secondary (but not both).
Almost any transformer will work and any speaker will be suitable.
If you use the speaker transformer described in the Home Made Speaker Transformer article, use one-side of the primary.
TRANSISTOR TESTER-1
CIRCUIT
Friday, October 10, 2014
LM3909 Continuity tester circuit diagram circuits and explanation
A very simple continuity tester electronic project can be designed using the LM3909 LED flasher integrated circuit .
This continuity tester project , require few external electronic parts and can be used for testing continuity of coils and cables .
This continuity tester project must be powered from a 1.5 volt DC power supply , you can use a 1.5 volts battery cell .
Wednesday, September 24, 2014
Digital Logic Tester Probe Circuit
This is not our first high and low tester, but the present circuit offers something new: a seven-segment display which shows ’H’ or ’L’ and at the same time a small loudspeaker , emits a corresponding tone.
And all that at very reasonable cost. When the supply is switched on, the decimal point of the display lights and indicates that the unit is ready i for use. If this is not the case, 0r an undefined signal is applied to the input, the display, apart from the decimal point, remains dark and the loudspeaker remains silent. If the input signal is logic 0, the display shows ’L and the loudspeaker emits a low note. When the input signal is logic 1, the display shows H’ and the loudspeaker emits a note which is an octave higher than the low tone. Operation of the circuit can be seen from the circuit diagram in figure 1 and the truth table in figure 2. When the input signal is 1, transistor T1 conducts taking the input of gate N2 above the trigger threshold and the trigger output goes to logic O. Transistor T2 (PNP!) is cut off, the input of gate N1 is also above the trigger threshold and this trigger output is therefore also logic 0. Both switching transistors T3 and T4 are off and a current flows through the corresponding segments (b, c, e, f, g), diodes D4 and D5 and R7. When the input signal is logic O, T1 is cut off and T2 conducts. The voltage at the inputs of gates N1 and N2 are below the trigger threshold and both outputs are logic 1, switching on transistors T3 and T4; the emitter voltage of T4 rises and cuts off diodes D4 and D5. This causes a current to flow through segments d, e and f, diodes D2 and D3, resistor R6 and transistor T3. With non—defined inputs (between 0.8.. . 2.15 V) and an open circuit input, both input transistors are cut off. The output of N1 is then logic O and that of N2 is logic 1: no current can therefore flow through any of the segments. As regards the drive for the two oscillators, suffice it to say that during low inputs N3 is driven by the output of N1 and during high in- puts N4 is driven directly by T1. lf required, the loudspeaker can be switched on by means of S1. The switch can, of course, be omitted_if the audio tone is always required. If you have an ear for music, R10 and R12 may be replaced by a 220 Q. resistor and a 250 SZ preset potentiometer so that the tone can be adjusted to your particular liking.!
Subscribe to:
Posts (Atom)
