Current indicator

G Schumann 561current indicator P1 1 O ® 1 = input 2 = limiting circuit 3 = ground 4 = reference voltage 5= output 6 = ground - 35-40V ICI R2 5W 5W (i) OEM am R1 E T6...T9 = BC 547B T2...T5 = BC 557B D6...D13 = 1N4148 C2 Ism 100p 63V R3[1 R16 C 12 D13 Who has not sometimes wished that the power supply he was using had a voltmeter AND an ammeter? Unfortu- nately, the high cost of such units pro- hibits their use in many situations. The proposed circuit, which does not include the input section of the power supply, can be built from stan- dard components, except for the low- value 5-watt resistors. We shall not dwell on the well-known Type L200 voltage regulator, but shall confine ourselves to the current indi- cator section. Fig. 1 shows that the circuit contains five LEDs: one (Di) to show whether the supply is switched on, and the other four to indicate the current con- sumption in steps of 0.5 A; 0.8 A; 1.3 A; and 1.8 A. As may be deduced from these figures, the unit is capable...