Summary The initial state of an SR (set-reset) latch is, in principle, indeterminate. The circuit is a SR (set-reset) latch with a power-on reset (POR), so that the initial state after power-on is determined. Circuit Schematic Transistor T3 is off while capacitor C1 charges through resistor R5. Consequently, the voltage at the collector of T1_L […]

Countdown Mk 1

Summary A three-digit initial state, determined by three 4-position dualĀ inline (DIL) switches, is set by pressing Switch 1 (SW1). Pressing Switch 2 (SW2) starts a count down to zero. When zero is reached, the light emitting diode (LED) lights up. The progress of the count is shown by a three-digit seven-segment liquid crystal display (LCD). […]