wheatstone bridge demonstration circuit

Small demonstration from one of the important and sensitive electric/electronic measurement circuits.The resistors must be completely identical to null all current through the micro ampere meter out. If not, the pointer will move (application one: resistance measurement). If the resistors are not completely identical, you can align the bridge by using 1 potentiometer (somewhat higher value, connect it between the wiper and 1 electrode) instead of a resistor. With this potentiometer you can null it out manually. When one of the resistors is temperature sensitive you have a sensitive analog temperature meter. Make a test circuit and bridge the resistors with your finger to gain more insight in the applications (e.g. how you want to use the temperature sensor) and all the things you can do with the circuit. Another application: sensitive analog light/photo sensor (1 light/photo dependent resistor in the bridge). Also useful as current direction detector in electrolysis experiments, touch detector, lie detector, small AC or DC voltages detector (with a transistor, see video), etc. etc. More circuits in my books, available on the Lulu website (author Ko Tilman). LINKS TO INFORMATIVE & GENERAL VIDEOS ABOUT ELECTRONICS What do you need for an electronic lab? https://youtu.be/v503bmymCWw How to test a power supply https://youtu.be/BeNoSmm3D_4 Elementary electronics, the bipolar transistor part 1 https://youtu.be/6tBdTzv3ENM Elementary electronics, the bipolar transistor part 2 https://youtu.be/maGOrqh_5-Q Elementary electronics: coils https://youtu.be/Lbb5nvlY0TE Elementary electronics: how to damage a bipolar transistor immediately (VERY important) https://youtu.be/VkeNKFqgsko The most important properties from bipolar transistors https://youtu.be/-mTjz4E5ua8 Prevent transistor leads from breaking https://youtu.be/iEe37oz4tww Combining NPN and PNP transistors in 1 circuit https://youtu.be/jfchBvkM4YA How to make a standard NPN Darlington https://youtu.be/D_WzRkFCCyo What to do with a transistor Darlington https://youtu.be/FrT395Nf6HI How to drive a relay by means of a transistor or Darlington https://youtu.be/R7cvddqVn18 Discriminating European transistor types https://youtu.be/LnpdBI3kJOE 2N3055 with a too low amplification factor, throw them away ? https://youtu.be/y_eW6xLiOKM The importance from the emitter capacitor in a grounded emitter transistor circuit https://youtu.be/br8iXVXRVl4 The transistor series regulator practice (hum suppressor!) https://youtu.be/YL41FPH_H-s How to make a shunt – DC ampèremeter https://youtu.be/FN59W9SGou4 Diodes, their voltage drop and its practical application https://youtu.be/vBv49BDznIA Passive diodes testing (barrier voltage) https://youtu.be/EI0-fj--Jjk Passive diode testing part 2 (capacitance-barrier layer) https://youtu.be/oKIcbubaUWw Point contact diodes https://youtu.be/Hgxm37foGww Electron tubes, some basics https://youtu.be/5a0NnfjGQw0 Do our ears make harmonics? https://youtu.be/2909D9o-Rs4 Oscillation