A Transistor Trigger Circuit Available to Purchase

Analysis of the characteristic curves of transistors shows that the negative resistance necessary to the functioning of a trigger circuit exists in the base circuit of a transistor. A trigger circuit may therefore be formed by inserting a resistance of proper magnitude in series with the base. Such a circuit has the advantages over vacuum‐tube circuits of much shorter triggering time, simplicity, small size, absence of filament power supply, and low operating voltage. The rise and fall times of the output voltage are less than 0.1 microsecond and the circuit is stable from zero triggering frequency up to the maximum frequency used. Although the circuit has been tested only up to 1 Mc, an upper limit of at least 10 Mc is probable. An output voltage of 5 or 6 volts may be readily obtained. Like other types of trigger circuit, the transistor circuit may be converted into a relaxation oscillator or a pulse generator.