276
Fig. 3.78:
Circuit 78 –
Quiztimer 3 seconds
Fig. 3.79:
Circuit
79 – Quiztimer 8
seconds
Circuit 78 – 80: Button S1 is used to fully charge the electrolytic capacitor C1/C2. At R2 discharge occurs. For
as long as the capacitor voltage exceeds the threshold voltage of T1 plus T2, T2 remains connected, LED1 is
lit.
Summary of Contents for ELECTRONICS EXPERIMENTS BOX
Page 4: ......
Page 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Page 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Page 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Page 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
